Question

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

Answer 1

(x+y)^2 - (x-y)^2 = x^2 + 2xy + y^2 - (x^2 - 2xy + y^2)
= x^2 + 2xy + y^2 - x^2 + 2xy - y^2)
= x^2 - x^2 + y^2 - y^2 + 2xy + 2xy
= 0 + 0 + 4xy
= 4xy
Sekian V(^_^)

Answer 2

   (x+y)² - (x-y)² 
= x² + 2xy + y² - (x² - 2xy + y²)
= x² + 2xy + y² - x² + 2xy - y²)
= x² - x² + y² - y² + 2xy + 2xy
= 0 + 0 + 4xy
= 4x y