Question

6. Using identities find the value of the following. i.68^ 2 -32^ 2 ii.101*99​

Answer 1

Answer:

1. 68^2- 32^2    

Using identity (a+b)(a-b)= a^2-b^2

68^2 - 32^2 = (68+32)(68-32)

                     = 100 x 36

                     = 3600

2. 101 x 99

101 can be written as (100-1)

99 can be written as (99+1)

Hence, 101 x 99 = (100-1)(100+1)

Using identity (a+b)(a-b)= a^2-b^2    

(100-1)(100+1) = (100)^2 - (1)^2

                        = 10000-1

                        = 9999