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NCERT Solutions for Class 9 Maths Chapter 2 Polynomials

NCERT Solutions for Class 9 Maths Chapter 2 Polynomials

Edited By Komal Miglani | Updated on Apr 10, 2025 09:27 PM IST

Have you noticed how your score in a video game increases with each level you pass? Or how your savings grow month after month? Well, they don't just change randomly; they follow a certain pattern, that's what the Polynomials are all about. For example, a second-order polynomial (highest exponent 2) like 2x2+5x+2 can represent how your score increases as you progress through a game where x is the game level. In the second chapter of the NCERT Class 9 Maths, you will find Polynomials, which are algebraic expressions of variables and coefficients - sound complex? Don't worry, we will break it down in a simple and logical manner that will help you build your foundation in algebra.

This Story also Contains
  1. Polynomials Class 9 Questions And Answers PDF Free Download
  2. Polynomials Class 9 Solutions - Important Formulae
  3. Polynomials Class 9 NCERT Solutions
  4. Polynomials Class 9 Solutions - Exercise Wise
  5. NCERT Solutions For Class 9 Maths - Chapter Wise
  6. Importance of Solving NCERT Questions of Class 9 Maths Chapter 2
  7. NCERT Solutions For Class 9 - Subject Wise
  8. NCERT Class 9 Books and Syllabus
NCERT Solutions for Class 9 Maths Chapter 2 Polynomials
NCERT Solutions for Class 9 Maths Chapter 2 Polynomials

This article on NCERT solutions for class 9 Maths Chapter 2 Polynomials offers clear and step-by-step solutions for the exercise problems in the NCERT Books for class 9 Maths. Students who are in need of Polynomials class 9 solutions will find this article very useful. It covers all the important Class 9 Maths Chapter 2 question answers. These Polynomials class 9 ncert solutions are made by the Subject Matter Experts according to the latest CBSE syllabus, ensuring that students can grasp the basic concepts effectively. NCERT solutions for class 9 maths and NCERT solutions for other subjects and classes can be downloaded from the NCERT Solutions.

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Polynomials Class 9 Questions And Answers PDF Free Download

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Polynomials Class 9 Solutions - Important Formulae

The general form of a polynomial is: p(x) = anxn + an-1xn-1 + … + a2x2 + a1x + a0

where a0, a1, a2, …., an are constants, and an ≠ 0.

Every one-variable linear polynomial will contain a unique zero, which is a real number that is a zero of the zero polynomial, and a non-zero constant polynomial that does not have any zeros.

Remainder Theorem: If p(x) has a degree greater than or equal to 1, and you divide p(x) by the linear polynomial (x - a), the remainder will be p(a).

Factor Theorem: The linear polynomial (xa) will be a factor of the polynomial p(x) whenever p(a) = 0. Similarly, if (xa) is a factor of p(x), then p(a) = 0.

Polynomials Class 9 NCERT Solutions

NCERT Polynomials class 9 solutions Exercise: 2.1
Page number: 29, Total questions: 5

Q1. (i) Is the following expression a polynomial in one variable? State reasons for your answer.
4x23x+7

Answer:

Yes, the polynomial 4x23x+7 has only one variable, which is x.

Q1. (ii) Is the following expression a polynomial in one variable? State reasons for your answer.
y2+2

Answer:

YES
Given polynomial has only one variable which is y.

Q1. (iii) Is the following expression polynomial in one variable? State reasons for your answer.
3t+t2

Answer:

NO
Because we can observe that the exponent of variable t in term 3t is 12 which is not a whole number.
Therefore, this expression is not a polynomial.

Q1. (iv) Is the following expression polynomial in one variable? State reasons for your answer.
y+2y

Answer:

NO
Because we can observe that the exponent of variable y in term 2y is 1 which is not a whole number. Therefore this expression is not a polynomial.

Q1. (v) Is the following expression polynomial in one variable? State reasons for your answer.
x10+y3+t50

Answer:

NO
Because in the given polynomial x10+y3+t50 there are 3 variables which are x, y, t. That's why this is a polynomial in three variables, not in one variable.

Q2. (i) Write the coefficients of x2 in the following: 2+x2+x

Answer:

Coefficient of x2 in polynomial 2+x2+x is 1.

Q2. (ii) Write the coefficients of x2 in the following: 2x2+x3

Answer:

The coefficient of x2 in polynomial 2x2+x3 is -1.

Q2. (iii) Write the coefficients of x2 in the following: π2x2+x

Answer:

Coefficient of x2 in polynomial π2x2+x is π2

Q2. (iv) Write the coefficients of x2 in the following: 2x1

Answer:

Coefficient of x2 in polynomial 2x1 is 0

Q3 Give one example each of a binomial of degree 35, and of a monomial of degree 100.

Answer:

The degree of a polynomial is the highest power of the variable in the polynomial.
In binomial, there are two terms
Therefore, a binomial of degree 35 is
Eg: x35+1
In a monomial, there is only one term in it.
Therefore, a monomial of degree 100 can be written as y100

Q4. (i) Write the degree the following polynomial: 5x3+4x2+7x

Answer:

The degree of a polynomial is the highest power of the variable in the polynomial.
Therefore, the degree of the polynomial 5x3+4x2+7x is 3.

Q4. (ii) Write the degree the following polynomial: 4y2

Answer:

The degree of a polynomial is the highest power of the variable in the polynomial.

Therefore, the degree of polynomial 4y2 is 2.

Q4. (iii) Write the degree the following polynomial: 5t7

Answer:

The degree of a polynomial is the highest power of the variable in the polynomial.

Therefore, the degree of polynomial 5t7 is 1

Q4. (iv) Write the degree the following polynomial: 3

Answer:

The degree of a polynomial is the highest power of the variable in the polynomial.

In this case, only a constant value 3 is there and the degree of a constant polynomial is always 0.

Q5. (i) Classify the following as linear, quadratic and cubic polynomial: x2+x

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial has its degrees as 1, 2, and 3 respectively

Given polynomial is x2+x with degree 2

Therefore, it is a quadratic polynomial.

Q5. (ii) Classify the following as linear, quadratic and cubic polynomials: xx3

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial have its degrees as 1, 2, and 3, respectively
Given polynomial is xx3 with degree 3
Therefore, it is a cubic polynomial

Q5 (iii) Classify the following as linear, quadratic and cubic polynomials: y+y2+4

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial have its degrees as 1, 2, and 3, respectively

Given polynomial is y+y2+4 with degree 2.

Therefore, it is a quadratic polynomial.

Q5. (iv) Classify the following as linear, quadratic and cubic polynomials: 1+x

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial has its degrees as 1, 2, and 3 respectively

Given polynomial is 1+x with degree 1

Therefore, it is linear polynomial

Q5. (v) Classify the following as linear, quadratic and cubic polynomial: 3t

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial has its degrees as 1, 2, and 3 respectively

Given polynomial is 3t with degree 1

Therefore, it is a linear polynomial

Q5. (vi) Classify the following as linear, quadratic and cubic polynomials: r2

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial have their degrees as 1, 2, and 3, respectively

Given polynomial is r2 with degree 2

Therefore, it is a quadratic polynomial

Q5. (vii) Classify the following as linear, quadratic and cubic polynomials: 7x3

Answer:

Linear polynomial, quadratic polynomial, and cubic polynomial have their degrees as 1, 2, and 3, respectively

Given polynomial is 7x3 with degree 3

Therefore, it is a cubic polynomial.

Polynomials class 9 NCERT solutions Exercise: 2.2
Page number: 31-32, Total questions: 4

Q1. (i) Find the value of the polynomial 5x4x2+3 at x=0

Answer:

Given polynomial is 5x4x2+3

Now, at x=0 value is

5(0)4(0)2+3=00+3=3

Therefore, value of polynomial 5x4x2+3 at x = 0 is 3

Q1. (ii) Find the value of the polynomial 5x4x2+3 at x=1

Answer:

Given polynomial is 5x4x2+3

Now, at x=1 value is

5(1)4(1)2+3=54+3=6

Therefore, value of polynomial 5x4x2+3 at x = -1 is -6

Q1. (iii) Find the value of the polynomial 5x4x2+3 at x=2

Answer:

Given polynomial is 5x4x2+3

Now, at x=2 value is

5(2)4(2)2+3=1016+3=3

Therefore, value of polynomial 5x4x2+3 at x = 2 is -3

Q2. (i) Find p(0) , p(1) and p(2) for each of the following polynomials: p(y)=y2y+1

Answer:

Given polynomial is

p(y)=y2y+1

Now,

p(0)=(0)20+1=1

p(1)=(1)21+1=1

p(2)=(2)22+1=3

Therefore, values of p(0) , p(1) and p(2) are 1 , 1 and 3 respectively .

Q2. (ii) Find p(0) , p(1) and p(2) for each of the following polynomials: p(t)=2+t+2t2t3

Answer:

Given polynomial is

p(t)=2+t+2t2t3

Now,

p(0)=2+0+2(0)2(0)3=2

p(1)=2+1+2(1)2(1)3=4

p(2)=2+2+2(2)2(2)3=4

Therefore, values of p(0) , p(1) and p(2) are 2 , 4 and 4 respectively

Q2. (iii) Find p(0), p(1) and p(2) for each of the following polynomials: p(x)=x3

Answer:

Given polynomial is

p(x)=x3

Now,

p(0)=(0)3=0

p(1)=(1)3=1

p(2)=(2)3=8
Therefore, values of p(0) , p(1) and p(2) are 0 , 1 and 8 respectively

Q2. (iv) Find p(0), p(1) and p(2) for each of the following polynomials: p(x)=(x1)(x+1)

Answer:

Given polynomial is
p(x)=(x1)(x+1)=x21

Now,
p(0)=(0)21=1

p(1)=(1)21=0

p(2)=(2)21=3

Therefore, values of p(0) , p(1) and p(2) are -1 , 0 and 3 respectively

Q3. (i) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=3x+1,x=13

Answer:

Given polynomial is p(x)=3x+1

Now, at x=13 it's value is

p(13)=3×(13)+1=1+1=0

Therefore, yes x=13 is a zero of polynomial p(x)=3x+1

Q3. (ii) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=5xπ,x=45

Answer:

Given polynomial is p(x)=5xπ

Now, at x=45 it's value is

p(45)=5×(45)π=4π0
Therefore, no x=45 is not a zero of polynomial p(x)=5xπ

Q3. (iii) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=x21,x=1,1

Answer:

Given polynomial is p(x)=x21

Now, at x = 1 its value is

p(1)=(1)21=11=0

And at x = -1

p(1)=(1)21=11=0
Therefore, yes x = 1 , -1 are zeros of polynomial p(x)=x21

Q3. (iv) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=(x+1)(x2),x=1,2

Answer:

Given polynomial is p(x)=(x+1)(x2)

Now, at x = 2 it's value is

p(2)=(2+1)(22)=0

And at x = -1

p(1)=(1+1)(12)=0

Therefore, yes x = 2 , -1 are zeros of polynomial p(x)=(x+1)(x2)

Q3. (v) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=x2.x=0

Answer:

Given polynomial is p(x)=x2

Now, at x = 0 it's value is

p(0)=(0)2=0

Therefore, yes x = 0 is a zeros of polynomial p(x)=(x+1)(x2)

Q3. (vi) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=lx+m, x=ml

Answer:

Given polynomial is p(x)=lx+m

Now, at x=ml it's value is

p(ml)=l×(ml)+m=m+m=0

Therefore, yes x=ml is a zeros of polynomial p(x)=lx+m

Q3. (vii) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=3x21, x=13,23

Answer:

Given polynomial is p(x)=3x21

Now, at x=13 it's value is

p(13)=3×(13)21=11=0

And at x=23

p(23)=3×(23)21=41=30

Therefore, x=13 is a zeros of polynomial p(x)=3x21 .

whereas x=23 is not a zeros of polynomial p(x)=3x21

Q3. (viii) Verify whether the following are zeroes of the polynomial, indicated against it. p(x)=2x+1, x=12

Answer:

Given polynomial is p(x)=2x+1

Now, at x=12 it's value is

p(12)=2×(12)+1=1+1=20

Therefore, x=12 is not a zeros of polynomial p(x)=2x+1

Q4. (i) Find the zero of the polynomial in each of the following cases: p(x)=x+5

Answer:

Given polynomial is p(x)=x+5

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

x+5=0

x=5

Therefore, x = -5 is the zero of polynomial p(x)=x+5

Q4. (ii) Find the zero of the polynomial in each of the following cases: p(x)=x5

Answer:

Given polynomial is p(x)=x5

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

x5=0

x=5

Therefore, x = 5 is a zero of polynomial p(x)=x5

Q4. (iii) Find the zero of the polynomial in each of the following cases: p(x)=2x+5

Answer:

Given polynomial is p(x)=2x+5

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

2x+5=0

x=52

Therefore, x=52 is a zero of polynomial p(x)=2x+5

Q4. (iv) Find the zero of the polynomial in each of the following cases: p(x)=3x2

Answer:

Given polynomial is p(x)=3x2

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

3x2=0

x=23
Therefore, x=23 is a zero of polynomial p(x)=3x2

Q4. (v) Find the zero of the polynomial in each of the following cases: p(x)=3x

Answer:

Given polynomial is p(x)=3x

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

3x=0

x=0

Therefore, x=0 is a zero of polynomial p(x)=3x

Q4. (vi) Find the zero of the polynomial in each of the following cases: p(x)=ax, a0

Answer:

Given polynomial is p(x)=ax

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

ax=0

x=0

Therefore, x=0 is a zero of polynomial p(x)=ax

Q4. (vii) Find the zero of the polynomial in each of the following cases: p(x)=cx+d,c0,c,d are real numbers

Answer:

Given polynomial is p(x)=cx+d

Zero of a polynomial is that value of the variable at which the value of the polynomial is obtained as 0.

Now,

p(x)=0

cx+d=0

x=dc

Therefore, x=dc is a zero of polynomial p(x)=cx+d

Class 9 polynomials NCERT solutions Exercise: 2.3
Page number: 35-36, Total questions: 5

Q1. (i) Determine which of the following polynomials has (x+1) a factor : x3+x2+x+1

Answer:

Zero of polynomial (x+1) is -1.

If (x+1) is a factor of polynomial p(x)=x3+x2+x+1

Then, p(1) must be equal to zero

Now,

p(1)=(1)3+(1)21+1

p(1)=1+11+1=0

Therefore, (x+1) is a factor of polynomial p(x)=x3+x2+x+1

Q1. (ii) Determine which of the following polynomials has (x+1) a factor : x4+x3+x2+x+1

Answer:

Zero of polynomial (x+1) is -1.

If (x+1) is a factor of polynomial p(x)=x4+x3+x2+x+1

Then, p(1) must be equal to zero

Now,

p(1)=(1)4+(1)3+(1)21+1

p(1)=11+11+1=10

Therefore, (x+1) is not a factor of polynomial p(x)=x4+x3+x2+x+1

Q1. (iii) Determine which of the following polynomials has (x+1) a factor : x4+3x3+3x2+x+1

Answer:

Zero of polynomial (x+1) is -1.

If (x+1) is a factor of polynomial p(x)=x4+3x3+3x2+x+1

Then, p(1) must be equal to zero

Now,

p(1)=(1)4+3(1)3+3(1)21+1

p(1)=13+31+1=10

Therefore, (x+1) is not a factor of polynomial p(x)=x4+3x3+3x2+x+1

Q1. (iv) Determine which of the following polynomials has (x+1) a factor : x3x2(2+2)x+2

Answer:

Zero of polynomial (x+1) is -1.

If (x+1) is a factor of polynomial p(x)=x3x2(2+2)x+2

Then, p(1) must be equal to zero

Now,

p(1)=(1)3(1)2(2+2)(1)+2

p(1)=11+2+2+2=220

Therefore, (x+1) is not a factor of polynomial p(x)=x3x2(2+2)x+2

Q2. (i) Use the Factor Theorem to determine whether g(x) is a factor of p(x) in the following case: p(x)=2x3+x22x1, g(x)=x+1

Answer:

Zero of polynomial g(x)=x+1 is 1

If g(x)=x+1 is factor of polynomial p(x)=2x3+x22x1

Then, p(1) must be equal to zero

Now,

p(1)=2(1)3+(1)22(1)1

p(1)=2+1+21=0

Therefore, g(x)=x+1 is factor of polynomial p(x)=2x3+x22x1

Q2. (ii) Use the Factor Theorem to determine whether g(x) is a factor of p(x) in the following case: p(x)=x3+3x2+3x+1, g(x)=x+2

Answer:

Zero of polynomial g(x)=x+2 is 2

If g(x)=x+2 is factor of polynomial p(x)=x3+3x2+3x+1

Then, p(2) must be equal to zero

Now,

p(2)=(2)3+3(2)2+3(2)+1

p(2)=8+126+1=10

Therefore, g(x)=x+2 is not a factor of polynomial p(x)=x3+3x2+3x+1

Q2. (iii) Use the Factor Theorem to determine whether g(x) is a factor of p(x) in the following case: p(x)=x34x2+x+6, g(x)=x3

Answer:

Zero of polynomial g(x)=x3 is 3

If g(x)=x3 is factor of polynomial p(x)=x34x2+x+6

Then, p(3) must be equal to zero

Now,

p(3)=(3)34(3)2+3+6

p(3)=2736+3+6=0

Therefore, g(x)=x3 is a factor of polynomial p(x)=x34x2+x+6

Q3. (i) Find the value of k , if x1 is a factor of p(x) in the following case: p(x)=x2+x+k

Answer:

Zero of polynomial x1 is 1

If x1 is factor of polynomial p(x)=x2+x+k

Then, p(1) must be equal to zero

Now,

p(1)=(1)2+1+k

p(1)=0

2+k=0

k=2

Therefore, the value of k is 2

Q3. (ii) Find the value of k , if x1 is a factor of p(x) in the following case: p(x)=2x2+kx+2

Answer:

Zero of the polynomial x1 is 1

If x1 is factor of polynomial p(x)=2x2+kx+2

Then, p(1) must be equal to zero

Now,

p(1)=2(1)2+k(1)+2

p(1)=0

2+k+2=0

k=(2+2)

Therefore, the value of k is (2+2)

Q3. (iii) Find the value of k , if x1 is a factor of p(x) in the following case: p(x)=kx22x+1

Answer:

Zero of polynomial x1 is 1

If x1 is factor of polynomial p(x)=kx22x+1

Then, p(1) must be equal to zero

Now,

p(1)=k(1)22(1)+1

p(1)=0

k2+1=0

k=1+2

Therefore, the value of k is 1+2

Q3. (iv) the value of k , if x1 is a factor of p(x) in the following case: p(x)=kx23x+k

Answer:

Zero of polynomial x1 is 1

If x1 is factor of polynomial p(x)=kx23x+k

Then, p(1) must be equal to zero

Now,

p(1)=k(1)23(1)+k

p(1)=0

k3+k=0

k=32
Therefore, value of k is 32

Q4. (i) Factorise : 12x27x+1

Answer:

Given polynomial is 12x27x+1

We need to factorise the middle term into two terms such that their product is equal to 12×1=12 and their sum is equal to 7

We can solve it as

12x27x+1

12x23x4x+1 (3×4=12  and  3+(4)=7)

3x(4x1)1(4x1)

(3x1)(4x1)

Q4. (ii) Factorise : 2x2+7x+3

Answer:

Given polynomial is 2x2+7x+3

We need to factorise the middle term into two terms such that their product is equal to 2×3=6 and their sum is equal to 7

We can solve it as

12x27x+1

2x2+6x+x+3 (6×1=6  and  6+1=7)

2x(x+3)+1(x+3)

(2x+1)(x+3)

Q4. (iii) Factorise : 6x2+5x6

Answer:

Given polynomial is 6x2+5x6

We need to factorise the middle term into two terms such that their product is equal to 6×6=36 and their sum is equal to 5

We can solve it as

6x2+5x6

6x2+9x4x6 (9×4=36  and  9+(4)=5)

3x(2x+3)2(2x+3)

(2x+3)(3x2)

Q4. (iv) Factorise : 3x2x4

Answer:

Given polynomial is 3x2x4

We need to factorise the middle term into two terms such that their product is equal to 3×4=12 and their sum is equal to 1

We can solve it as

3x2x4

3x24x+3x4 (3×4=12  and  3+(4)=1)

x(3x4)+1(3x4)

(x+1)(3x4)

Q5. (i) Factorise : x32x2x+2

Answer:

Given polynomial is x32x2x+2

Now, by hit and trial method we observed that (x+1) is one of the factors of the given polynomial.

By the long division method, we will get

1639996302612

We know that Dividend = (Divisor × Quotient) + Remainder

x32x2x+2=(x+1)(x23x+2)+0

=(x+1)(x22xx+2)

=(x+1)(x2)(x1)

Therefore, on factorization of x32x2x+2 we will get (x+1)(x2)(x1)

Q5. (ii) Factorise : x33x29x5

Answer:

Given polynomial is x33x29x5

Now, by the hit-and-trial method, we observed that (x+1) is one of the factors of the given polynomial.

By the long division method, we will get

1639996323635

We know that Dividend = (Divisor × Quotient) + Remainder

x33x29x5=(x+1)(x24x5)

=(x+1)(x25x+x5)

=(x+1)(x5)(x+1)

Therefore, on factorization of x33x29x5 we will get (x+1)(x5)(x+1)

Q5. (iii) Factorise : x3+13x2+32x+20

Answer:

Given polynomial is x3+13x2+32x+20

Now, by hit and trial method we observed that (x+1) is one of the factors of given polynomial.

By long division method, we will get

1639996347806

We know that Dividend = (Divisor × Quotient) + Remainder

x3+13x2+32x+20=(x+1)(x2+12x+20)

=(x+1)(x2+10x+2x+20)

=(x+1)(x+10)(x+2)

Therefore, on factorization of x3+13x2+32x+20 we will get (x+1)(x+10)(x+2)

Q5. (iv) Factorise : 2y3+y22y1

Answer:

Given polynomial is 2y3+y22y1

Now, by hit and trial method we observed that (y1) is one of the factors of the given polynomial.

By long division method, we will get

1639996378575

We know that Dividend = (Divisor × Quotient) + Remainder

2y3+y22y1=(y1)(2y2+3y+1)

=(y1)(2y2+2y+y+1)

=(y1)(2y+1)(y+1)

Therefore, on factorization of 2y3+y22y1 we will get (y1)(2y+1)(y+1).

Class 9 maths chapter 2 question answer Exercise: 2.4
Page number: 40-42, Total questions: 16

Q1. (i) Use suitable identities to find the following product: (x+4)(x+10)

Answer:

We will use identity

(x+a)(x+b)=x2+(a+b)x+ab

Put a=4  and  b=10

(x+4)(x+10)=x2+(10+4)x+10×4

=x2+14x+40

Therefore, (x+4)(x+10) is equal to x2+14x+40

Q1. (ii) Use suitable identities to find the following product: (x+8)(x10)

Answer:

We will use identity

(x+a)(x+b)=x2+(a+b)x+ab

Put a=8  and  b=10

(x+8)(x10)=x2+(10+8)x+8×(10)

=x22x80

Therefore, (x+8)(x10) is equal to x22x80

Q1. (iii) Use suitable identities to find the following product: (3x+4)(3x5)

Answer:

We can write (3x+4)(3x5) as

(3x+4)(3x5)=9(x+43)(x53)

We will use identity

(x+a)(x+b)=x2+(a+b)x+ab

Put a=43  and  b=53

9(x+43)(x53)=9(x2+(4353)x+43×(53))

=9x23x20

Therefore, (3x+4)(3x5) is equal to 9x23x20

Q1. (iv) Use suitable identities to find the following product: (y2+32)(y232)

Answer:

We will use identity

(x+a)(xa)=x2a2

Put x=y2  and  a=32

(y2+32)(y232)=(y2)2(32)2

=y494

Therefore, (y2+32)(y232) is equal to y494

Q1. (v) Use suitable identities to find the following product: (32x)(3+2x)

Answer:

We can write (32x)(3+2x) as

(32x)(3+2x)=4(x32)(x+32)

We will use identity

(x+a)(xa)=x2a2

Put a=32

4(x+32)(x32)=4((x)2(32)2)

=94x2

Therefore, (32x)(3+2x) is equal to 94x2

Q2. (i) Evaluate the following product without multiplying directly: 103×107

Answer:

We can rewrite 103×107 as

103×107=(100+3)×(100+7)

We will use identity

(x+a)(x+b)=x2+(a+b)x+ab

Put x=100,a=3  and  b=7

(100+3)×(100+7)=(100)2+(3+7)100+3×7

=10000+1000+21=11021

Therefore, value of 103×107 is 11021

Q2. (ii) Evaluate the following product without multiplying directly: 95×96

Answer:

We can rewrite 95×96 as

95×96=(1005)×(1004)

We will use identity

(x+a)(x+b)=x2+(a+b)x+ab

Put x=100,a=5  and  b=4

(1005)×(1004)=(100)2+(54)100+(5)×(4)

=10000900+20=9120

Therefore, value of 95×96 is 9120

Q2. (iii) Evaluate the following product without multiplying directly: 104×96

Answer:

We can rewrite 104×96 as

104×96=(100+4)×(1004)

We will use identity

(x+a)(xa)=x2a2

Put x=100  and  a=4

(100+4)×(1004)=(100)2(4)2

=1000016=9984

Therefore, value of 104×96 is 9984

Q3. (i) Factorise the following using appropriate identities: 9x2+6xy+y2

Answer:

We can rewrite 9x2+6xy+y2 as

9x2+6xy+y2=(3x)2+2×3x×y+(y)2

Using identity (a+b)2=(a)2+2×a×b+(b)2

Here, a=3x  and  b=y

Therefore,

9x2+6xy+y2=(3x+y)2=(3x+y)(3x+y)

Q3. (ii) Factorise the following using appropriate identities: 4y24y+1

Answer:

We can rewrite 4y24y+1 as

4y24y+1=(2y)22×2y×1+(1)2

Using identity (ab)2=(a)22×a×b+(b)2

Here, a=2y  and  b=1

Therefore,

4y24y+1=(2y1)2=(2y1)(2y1)

Q3. (iii) Factorise the following using appropriate identities: x2y2100

Answer:

We can rewrite x2y2100 as

x2y2100=(x)2(y10)2

Using identity a2b2=(ab)(a+b)

Here, a=x  and  b=y10

Therefore,

x2y2100=(xy10)(x+y10)

Q4. (i) Expand each of the following, using suitable identities: (x+2y+4z)2

Answer:

Given is (x+2y+4z)2

We will Use identity

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

Here, a=x,b=2y  and  c=4z

Therefore,

(x+2y+4z)2=(x)2+(2y)2+(4z)2+2.x.2y+2.2y.4z+2.4z.x

=x2+4y2+16z2+4xy+16yz+8zx

Q4. (ii) Expand each of the following, using suitable identities: (2xy+z)2

Answer:

Given is (2xy+z)2

We will Use identity

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

Here, a=2x,b=y  and  c=z

Therefore,

(2xy+z)2=(2x)2+(y)2+(z)2+2.2x.(y)+2.(y).z+2.z.2x

=4x2+y2+z24xy2yz+4zx

Q4. (iii) Expand each of the following, using suitable identities: (2x+3y+2z)2

Answer:

Given is (2x+3y+2z)2

We will Use identity

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

Here, a=2x,b=3y  and  c=2z

Therefore,

(2x+3y+2z)2=(2x)2+(3y)2+(2z)2+2.(2x).3y+2.3y.2z+2.z.(2x)

=4x2+9y2+4z212xy+12yz8zx

Q4. (iv) Expand each of the following, using suitable identities: (3a7bc)2

Answer:

Given is (3a7bc)2

We will Use identity

(x+y+z)2=x2+y2+z2+2xy+2yz+2zx

Here, x=3a,y=7b  and  z=c

Therefore,

(3a7bc)2=(3a)2+(7b)2+(c)2+2.3a.(7b)+2.(7b).(c)+2.(c) .3a

=9a2+49b2+c242ab+14bc6ca

Q4. (v) Expand each of the following, using suitable identities: (2x+5y3z)2

Answer:

Given is (2x+5y3z)2

We will Use identity

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

Here, a=2x,b=5y  and  c=3z

Therefore,

(2x+5y3z)2 =(2x)2+(5y)2+(3z)2+2.(2x).5y+2.5y.(3z)+2.(3z).(2x)

=4x2+25y2+9z220xy30yz+12zx

Q4. (vi) Expand each of the following, using suitable identities: [14a12b+1]2

Answer:

Given is [14a12b+1]2

We will Use identity

(x+y+z)2=x2+y2+z2+2xy+2yz+2zx

Here, x=a4,y=b2  and  z=1

Therefore,

[14a12b+1]2 =(a4)2+(b2)2+(1)2+2.(a4).(b2)+2.(b2).1+2.1.(a4)

=a216+b24+1ab4b+a2

Q5. (i) Factorise: 4x2+9y2+16z2+12xy24yz16xz

Answer:

We can rewrite 4x2+9y2+16z2+12xy24yz16xz as

4x2+9y2+16z2+12xy24yz16xz =(2x)2+(3y)2+(4z)2+2.2x.3y+2.3y.(4z)+2.(4z).2x

We will Use identity

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

Here, a=2x,b=3y  and  c=4z

Therefore,

4x2+9y2+16z2+12xy24yz16xz=(2x+3y4z)2

=(2x+3y4z)(2x+3y4z)

Q5. (ii) Factorise: 2x2+y2+8z222xy+42yz8xz

Answer:

We can rewrite 2x2+y2+8z222xy+42yz8xz as

2x2+y2+8z222xy+42yz8xz =(2x)2+(y)2+(22z)2+2.(2).y+2.y.22z+2.(2x).22z

We will Use identity

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

Here, a=2x,b=y  and  c=22z

Therefore,

2x2+y2+8z222xy+42yz8xz=(2x+y+22z)2

=(2x+y+22z)(2x+y+22z)

Q6 (i) Write the following cubes in expanded form: (2x+1)3

Answer:

Given is (2x+1)3

We will use identity

(a+b)3=a3+b3+3a2b+3ab2

Here, a=2x  and  b=1

Therefore,

(2x+1)3=(2x)3+(1)3+3.(2x)2.1+3.2x.(1)2

=8x3+1+12x2+6x

Q6. (ii) Write the following cube in expanded form: (2a3b)3

Answer:

Given is (2a3b)3

We will use identity

(xy)3=x3y33x2y+3xy2

Here, x=2a  and  y=3b

Therefore,

(2a3b)3=(2a)3(3b)33.(2a)2.3b+3.2a.(3b)2

=8a39b336a2b+54ab2

Q6. (iii) Write the following cube in expanded form: [32x+1]3

Answer:

Given is [32x+1]3

We will use identity

(a+b)3=a3+b3+3a2b+3ab2

Here, a=3x2  and  b=1

Therefore,

(3x2+1)3=(3x2)3+(1)3+3.(3x2)2.1+3.3x2.(1)2

=27x38+1+27x24+9x2

Q6. (iv) Write the following cube in expanded form: [x23y]3

Answer:

Given is [x23y]3

We will use identity

(ab)3=a3b33a2b+3ab2

Here, a=x and  b=2y3

Therefore,

[x23y]3=x3(2y3)33.x2.2y3+3.x.(2y3)2

=x38y3272x2y+4xy23

Q7. (i) Evaluate the following using suitable identities: (99)3

Answer:

We can rewrite (99)3 as

(99)3=(1001)3

We will use identity

(ab)3=a3b33a2b+3ab2

Here, a=100 and  b=1

Therefore,

(1001)1=(100)3(1)33.(100)2.1+3.100.12

=1000000130000+300=970299

Q7. (ii) Evaluate the following using suitable identities: (102)3

Answer:

We can rewrite (102)3 as

(102)3=(100+2)3

We will use identity

(a+b)3=a3+b3+3a2b+3ab2

Here, a=100 and  b=2

Therefore,

(100+2)1=(100)3+(2)3+3.(100)2.2+3.100.22

=1000000+8+60000+1200=1061208

Q7. (iii) Evaluate the following using suitable identities: (998)3

Answer:

We can rewrite (998)3 as

(998)3=(10002)3

We will use identity

(ab)3=a3b33a2b+3ab2

Here, a=1000 and  b=2

Therefore,

(10002)1=(1000)3(2)33.(0100)2.2+3.1000.22

=100000000086000000+12000=994011992

Q8. (i) Factorise the following: 8a3+b3+12a2b+6ab2

Answer:

We can rewrite 8a3+b3+12a2b+6ab2 as

8a3+b3+12a2b+6ab2 =(2a)3+(b)3+3.(2a)2.b+3.2a.(b)2

We will use identity

(x+y)3=x3+y3+3x2y+3xy2

Here, x=2a  and  y=b

Therefore,

8a3+b3+12a2b+6ab2=(2a+b)3

=(2a+b)(2a+b)(2a+b)

Q8. (ii) Factorise the following: 8a3b312a2b+6ab2

Answer:

We can rewrite 8a3b312a2b+6ab2 as

8a3b312a2b+6ab2 =(2a)3(b)33.(2a)2.b+3.2a.(b)2

We will use identity

(xy)3=x3y33x2y+3xy2

Here, x=2a  and  y=b

Therefore,

8a3b312a2b+6ab2=(2ab)3

=(2ab)(2ab)(2ab)

Q8. (iii) Factorise the following: 27125a3135a+225a2

Answer:

We can rewrite 27125a3135a+225a2 as

27125a3135a+225a2 =(3)3(25a)33.(3)2.5a+3.3.(5a)2

We will use identity

(xy)3=x3y33x2y+3xy2

Here, x=3  and  y=5a

Therefore,

27125a3135a+225a2=(35a)3

=(35a)(35a)(35a)

Q8. (iv) Factorise the following: 64a327b3144a2b+108ab2

Answer:

We can rewrite 64a327b3144a2b+108ab2 as

64a327b3144a2b+108ab2 =(4a)3(3b)33.(4a)2.3b+3.4a.(3b)2

We will use identity

(xy)3=x3y33x2y+3xy2

Here, x=4a  and  y=3b

Therefore,

64a327b3144a2b+108ab2=(4a3b)2

=(4a3b)(4a3b)(4a3b)

Q8. (v) Factorise the following: 27p3121692p2+14p

Answer:

We can rewrite 27p3121692p2+14p as

27p3121692p2+14p =(3p)3(16)33.(3p)2.16+3.3p.(16)2

We will use identity

(xy)3=x3y33x2y+3xy2

Here, x=3p  and  y=16

Therefore,

27p3121692p2+14p=(3p16)3

=(3p16)(3p16)(3p16)

Q9. (i) Verify: x3+y3=(x+y)(x2xy+y2)

Answer:

We know that

(x+y)3=x3+y3+3xy(x+y)

Now,

x3+y3=(x+y)33xy(x+y)

x3+y3=(x+y)((x+y)23xy)

x3+y3=(x+y)(x2+y2+2xy3xy) ((a+b)2=a2+b2+2ab)

x3+y3=(x+y)(x2+y2xy)

Hence proved.

Q9. (ii) Verify: x3y3=(xy)(x2+xy+y2)

Answer:

We know that

(xy)3=x3y33xy(xy)

Now,

x3y3=(xy)3+3xy(xy)

x3y3=(xy)((xy)2+3xy)

x3y3=(xy)(x2+y22xy+3xy) ((ab)2=a2+b22ab)

x3y3=(xy)(x2+y2+xy)

Hence proved.

Q10. (i) Factorise the following: 27y3+125z3

Answer:

We know that

a3+b3=(a+b)(a2+b2ab)

Now, we can write 27y3+125z3 as

27y3+125z3=(3y)3+(5z)3

Here, a=3y  and  b=5z

Therefore,

27y3+125z3=(3y+5z)((3y)2+(5z)23y.5z)

27y3+125z3=(3y+5z)(9y2+25z215yz)

Q10. (ii) Factorise the following: 64m3343n3

Answer:

We know that

a3b3=(ab)(a2+b2+ab)

Now, we can write 64m3343n3 as

64m3343n3=(4m)3(7n)3

Here, a=4m  and  b=7n

Therefore,

64m3343n3=(4m7n)((4m)2+(7n)2+4m.7n)

64m3343n3=(4m7n)(16m2+49n2+28mn)

Q11. Factorise: 27x3+y3+z39xyz

Answer:

Given is 27x3+y3+z39xyz

Now, we know that

a3+b3+c33abc=(a+b+c)(a2+b2+c2abbcca)

Now, we can write 27x3+y3+z39xyz as

27x3+y3+z39xyz =(3x)3+(y)3+(z)33.3x.y.z

Here, a=3x,b=y  and  c=z

Therefore,

27x3+y3+z39xyz =(3x+y+z)((3x)2+(y)2+(z)23x.yy.zz.3x)

=(3x+y+z)(9x2+y2+z23xyyz3zx).

Q12. Verify that x3+y3+z33xyz=12(x+y+z)[(xy)2+(yz)2+(zx)2]

Answer:

We know that

x3+y3+z33xyz=(x+y+z)(x2+y2+z2xyyzzx)

Now, multiply and divide the R.H.S. by 2

x3+y3+z33xyz=12(x+y+z)(2x2+2y2+2z22xy2yz2zx)

=12(x+y+z)(x2+y22xy+x2+z22zx+y2+z22yz)

=12(x+y+z)((xy)2+(yz)2+(zx)2) (a2+b22ab=(ab)2)

Hence proved.

Q13. If x+y+z=0 , show that x3+y3+z3=3xyz .

Answer:

We know that

x3+y3+z33xyz=(x+y+z)(x2+y2+z2xyyzzx)

Now, It is given that x+y+z=0

Therefore,

x3+y3+z33xyz=0(x2+y2+z2xyyzzx)

x3+y3+z33xyz=0

x3+y3+z3=3xyz

Hence proved.

Q14. (i) Without actually calculating the cubes, find the value of each of the following: (12)3+(7)3+(5)3

Answer:

Given is (12)3+(7)3+(5)3

We know that

If x+y+z=0 then , x3+y3+z3=3xyz

Here, x=12,y=7  and  z=5

x+y+z=12+7+5=0

Therefore,

(12)3+(7)3+(5)3=3×(12)×7×5=1260

Therefore, value of (12)3+(7)3+(5)3 is 1260

Q14. (ii) Without actually calculating the cubes, find the value of the following: (28)3+(15)3+(13)3

Answer:

Given is (28)3+(15)3+(13)3

We know that

If x+y+z=0 then , x3+y3+z3=3xyz

Here, x=28,y=15  and  z=13

x+y+z=281513=0

Therefore,

(28)3+(15)3+(13)3=3×(28)×(15)×(13)=16380

Therefore, value of (28)3+(15)3+(13)3 is 16380

Q15. (i) Give possible expressions for the length and breadth of the following rectangle, in which its area is given:

25a235a+12

Answer:

We know that

Area of rectangle is = length×breadth

It is given that area = 25a235a+12

Now, by splitting middle term method

25a235a+12=25a220a15a+12

=5a(5a4)3(5a4)

=(5a3)(5a4)
Therefore, two answers are possible

case (i) :- Length = (5a4) and Breadth = (5a3)

case (ii) :- Length = (5a3) and Breadth = (5a4)

Q15. (ii) Give possible expressions for the length and breadth of the following rectangle, in which its area is given:

35y2+13y12

Answer:

We know that

Area of rectangle is = length×breadth

It is given that area = 35y2+13y12

Now, by splitting the middle term method

35y2+13y12=35y2+28y15y12

=7y(5y+4)3(5y+4)

=(7y3)(5y+4)

Therefore, two answers are possible

case (i) :- Length = (5y+4) and Breadth = (7y3)

case (ii) :- Length = (7y3) and Breadth = (5y+4)

Q16. (i) What are the possible expressions for the dimensions of the cuboid whose volumes is given below?

Volume : 3x212x

Answer:

We know that

Volume of cuboid is = length×breadth×height

It is given that volume = 3x212x

Now,

3x212x=3×x×(x4)

Therefore,one of the possible answer is possible

Length = 3 and Breadth = x and Height = (x4)

Q16. (ii) What are the possible expressions for the dimensions of the cuboid whose volumes is given below?

Volume : 12ky2+8ky20k

Answer:

We know that

Volume of cuboid is = length×breadth×height

It is given that volume = 12ky2+8ky20k

Now,

12ky2+8ky20k=k(12y2+8y20)

=k(12y2+20y12y20)

=k(4y(3y+5)4(3y+5))

=k(3y+5)(4y4)

=4k(3y+5)(y1)

Therefore,one of the possible answer is possible

Length = 4k and Breadth = (3y+5) and Height = (y1).

Polynomials Class 9 Solutions - Exercise Wise

Students can practice Class 9 Maths Chapter 2 question answers using the exercise link given below.

NCERT Solutions For Class 9 Maths - Chapter Wise

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  • Students can practice various types of questions, which will improve their problem-solving skills.
  • These NCERT exercises cover all the important topics and concepts so that students can be well-prepared for various exams.
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NCERT Solutions For Class 9 - Subject Wise

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Maths chapter 2  includes five exercises covering topics such as Polynomials in one variable, Zeros of a Polynomial, Real Numbers and their Decimal Expansions, Representing Real Numbers on the Number Line, Operations on Real Numbers, and Laws of Exponents for Real Numbers. Practicing these exercises of NCERT maths class 9 chapter 2  is crucial for achieving a better understanding of the concepts and scoring well in Mathematics. To help students gain confidence, Careers360 experts have designed these solutions to provide comprehensive explanations of the concepts covered in this chapter.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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