Question

Помогите решить срочно!!! (x+y)^2-(x-y)^2

Answer 1

x^2+2xy+y^2-x^2+2xy-y^2=4xy.

Answer 2

(x+y)^2-(x-y)^2=(x+y-x+y)(x+y+x-y)=2y*2x=4xy