Question

Evaluate the following using identities:

(399)²

Answer 1

In the given problem, we have to evaluate expressions by using identities.

Given `(399)^2`

We can write`(399)^2 " as " (400 - 1)^2`

We shall use the Identity `(x - y)^2 - 2xy + y^2`

Where x = 400, y = 1

By applying in identity we get 

`(400 - 1)^2 = (400)^2 - 2 xx 400 xx 1 + (1)^2`

`= 400 xx 400 - 800 +  1`

= 16000 - 800 + 1

=159201

Hence the value of `(399)^2` is 159201