Question

using the identity a²-b²=(a+b)(a-b) solve (2m+n)²-(2m-n)²

Answer 1

(2m+n)^2- (2m- n)^2
=(2m+n+2m-n){2m+n-(2m-n)}
=4m× 2n
=8mn

Answer 2

Here is your answer...