Question

Evaluate (98 x 102) by using suitable identities.

Answer 1

The answer is 9996

Explanation:

Using the identity (x+a)(x+b) = x ^2 +(a+b)x+ab

Writing 102 as 100+2 and 98 as 100−2

Hence (100+2)(100−2) = 100 ^2 +[2+(−2)]100+(2)(−2)

= 10000+(0)100−4

= 9996

The answer is 9996

Answer 2

9996

Explanation:

by using suitable identities ;

• (98) × (102)
• (100 - 2) × (100 + 2)
• 10000 - 4
• 9996

identity used here is :

`(a + b) * (a - b) = (a {}^(2) - b {}^(2) )`

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