Question

quando simplificamos (x + y) (x - y) + (x + y )² - (x - y)² , obtemos:

Answer 1

(x+y)(x-y) + (x+y)² - (x-y)²

x²-y²+x²+2xy+y²-(x²-2xy+y²)

x²- y²+x²+2xy+y²-x²+2xy-y² = x²+4xy-y²