$$(x+y)^2 + (x-y)^2$$

How to find the difference between two sets of square numbers

When the sum of two sets of square numbers is asked, we can apply the following formula.

$$(x+y)^2 + (x-y)^2 = 2(x^2 + y^2)$$

Let us work it out with an example:-

let x=9 and y=7

$$(x+y)^2 + (x-y)^2 = 2(x^2 + y^2)$$

$$(9+7)^2 + (9-7)^2 = 2(9^2 + 7^2)$$

2(81 + 49)

2(130)

260