# Algebraic Expressions and Identities| Worksheet Solutions| Class 8

Worksheet solutions for chapter: Algebraic Expressions and Identities for class 8 are provided below.

(1)Add the following expressions 2a + 5 + 3a2, 7a2 + 6

Ans- (2) Find the product of 3a + 4 and 4a + 2

Ans-

(3a + 4) (4a + 2)

= 3a(4a + 2) + 4(4a + 2)

= 3a × 4a + 3a × 2 + 4 × 4a + 4 × 2

= 12a2 + 6a + 16a + 8

=12a2 + 22a + 8

Hence, product of given expressions is 12a2 + 22a + 8

(3) Subtract 12a + 2ab – 4b2 from 10a – 2ab + 5b2

Ans-

10a – 2ab + 5b2

12a + 2ab – 4b2

(-)    (-)      (+)

-2a            +b2

Hence, subtraction of given expressions is b2 – 2a

(4) Find the area rectangle whose length is a and breadth is b.

Ans- (5) Find the value of 108 × 92

Ans- (6) Find the value of (7a + 5b)2

Ans- (7) Complete the identities

(a) (a + b)2 = a2 +__ + ___

(b) a2 – b2 =

Ans-

(a) (a + b)2 = a2 + b2 + 2ab

(b) a2 – b2 = (a – b) (a + b)

(8) Find the product of (6a + 4b)( 2a + 9b)

Ans-

(6a + 4b)( 2a + 9b)

= 6a (2a + 9b) + 4b ( 2a + 9b)

= 6a × 2a + 6a × 9b + 4b × 2a + 4b × 9b

= 12a2 + 54ab + 8ab + 36b2

= 12a2 + 62ab + 36b2

Hence, product of given value is 12a2 + 62ab + 36b2

(9) Show that (7a + 8b)2 + 72ab = 49a2 + 64b2 – 40ab

Ans- (10) Show that 4a2 + 9b2 + 12ab – 24ab = (2a – 3b)2

Ans- Helping Topics

Algebraic Expressions and Identities

NCERT Solutions Class 8