# NCERT Solutions for Class 8 Maths chapter-9 Algebraic Expressions and Identities

NCERT solutions for class 8 maths chapter 9 Algebraic Expressions and Identities is prepared by academic team of Physics Wallah. We have prepared solutions for all exercise with importants questions of chapter 9. Given below is step by step solutions of all questions given in NCERT textbook for chapter-9. Read chapter 9 theory make sure you have gone through the theory part of chapter-9 from NCERT textbook and you have learned the formula of the given chapter. Physics Wallah prepared a detail notes and additional questions for class 8 maths with short notes of all maths formula of class 8 maths. do read these contents before moving to solve the exercise of NCERT chapter 9.

### NCERT Solutions for Class 8 Maths Exercise 9.1

Question 1.

Identify the terms, their coefficients for each of the following expressions:

(i)

(ii) 1 + x + x²

(iii)

(iv)3 - pq + qr -rp

(v) + - xy

(vi) 3 - pq + qr -rp

Solution :

(i) Terms:  and

Coefficient in is 5 and in is  -3

(ii) Terms: 1, x and

Coefficient of and coefficient of x²  is 1.

(iii) Terms:  and

Coefficient in is 4, coefficient of  is -4  and coefficient of is 1.

(iv) Terms: 3, -pq, qr  and -rp

Coefficient of -pq is -1, coefficient of qr is 1 and coefficient of -rp is

(v) Terms:  and  -xy

Coefficient of  is coefficient of is and coefficient of -xy is -1.

(vi) Terms:  0.3a, -0.6ab  and 0.5b

Coefficient of 0.3a  is 0.3, coefficient of -0.6ab  is -0.6 and coefficient of 0.5b  is 0.5.

Question 2.

Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories:

Solution :

(i) Since  contains two terms. Therefore it is binomial.

(ii) Since 1000 contains one terms. Therefore it is monomial.

(iii) Since contains four terms. Therefore it is a polynomial and it does not fit in above three categories.

(iv) Since contains three terms. Therefore it is trinomial.

(v) Since contains two terms. Therefore it is binomial.

(vi) Since contains three terms. Therefore it is trinomial.

(vii) Since contains three terms. Therefore it is trinomial.

(viii) Since contains two terms. Therefore it is binomial.

(ix) Since contains four terms. Therefore it is a polynomial and it does not fit in above three categories.

(x) Since pqr contains one terms. Therefore it is monomial.

(xi) Since contains two terms. Therefore it is binomial.

(xii) Since  2p + 2q contains two terms. Therefore it is binomial.

Question 3.

(i)

(ii)

(iii)

(iv)

Solution :

(i)

Hence the sum if 0.

Hence the sum is  ab + ac + bc.

Question 4.

Solution :

### NCERT Solutions for Class 8 Maths Exercise 9.2

Question 1.

Find the product of the following pairs of monomials:

(i)

(ii)

(iii)

(iv)

(iv) 4p ,0

Solution :

(i)   =  =

(ii) =

=

(iii) =

=

(iv) =

=

(v)=  = 0

Question 2.

Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively:

Solution :

(i)   Area of rectangle

=

=  sq. units

(ii) Area of rectangle

=

=

= 50mn sq. units

(iii) Area of rectangle  =

=

= sq. units

(iv) Area of rectangle  =

=

=  sq. units

(v) Area of rectangle  =

=

= sq. units

Question 3.

Complete the table of products:

(i)

Solution :

(i)

Question 4.

Obtain the volume of rectangular boxes with the following length, breadth and height respectively:

(i)

(ii)

(iii)

(iv)

Solution :

(i) Volume of rectangular box

=

= cubic units

(ii) Volume of rectangular box

=

=  cubic units

(iii) Volume of rectangular box

=

= cubic units

(iv) Volume of rectangular box

=

=  cubic units

Question 5.

Obtain the product of:

(i)

(ii)

(iii)

(iv)

(v)

Solution :

(i)

=

(ii) =

=

(iii)

=

(iv)

=

(v)

=

### NCERT Solutions for Class 8 Maths Exercise 9.3

Question 1.

Carry out the multiplication of the expressions in each of the following pairs:

(i)

(ii)

(iii)

(iv)

(v)

Solution :

(i)

=

(ii)

=

(iii)

=

(iv)

=

(v) =

= 0 + 0 + 0 = 0

Question 2.

Complete the table:

Solution :

Question 3.

Find the product:

(i)

(ii)

(iii)

(iv)

Solution :

(i)

=

(ii)

=

=

(iii)

=

=

(iv)  =

Question 4.

(a) Simplify: and find values for

(i)

(ii)

(b) Simplify: find its value for

(i)

(ii)

(iii)

Solution :

(a)

=

(i) For

=

= 108 – 45 + 3 = 66

(ii) For

=

=

=

(b)

=

(i)  For  a= 0,

=

= 0 + 0 + 0 + 5 = 5

(ii) For a = 1

=

= 1 + 1 + 1 + 5 = 8

(iii) For

=

= =4

Question 5.

(c) Subtract: from

(d) Subtract: from

Solution :

(a)

=

=

(b) +

=

=

=

(c)

=

=

=

(d)

=

=

=

=

=

=

NCERT Solutions for Class 8 Maths Exercise 9.4

Question 1.

Multiply the binomials:

(i)  and

(ii)  and

(iii)  and

(iv) and

(v)  and

(vi)  and

Solution :

(i)

=

=

=

(ii)

=

=

=

(iii)

=

=

=

(iv)

=

=

(v)

=

=

=

=

(vi)

=

=

=

Question 2.

Find the product:

(i)

(ii)

(iii)

(iv)

Solution :

(i)

=

= = 15 - x -2x²

(ii)

=

=

(iii)

=

=

(iv)

=

=

Question 3.

Simplify:

(i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

(viii)

Solution :

(i)

=

=

=

(ii)

=

=

=

(iii)

=

=

(iv)

=

=

=

= 4ac

(v)

=

=

=

(vi)

=

=

(vii)

=

=

=

(viii)

=

=

=

### Notes,worksheet and solved question for Maths class 8

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