Question

Упростить выражение
$frac{x+y}{x-y}$ - $frac{x-y}{x+y}$

Answer 1

$frac{ (x+y)^{2}- (x-y)^{2} }{(x-y)(x+y)} = frac{ (x+y-x+y)(x+y+x-y) }{(x-y)(x+y)}= frac{ 2y*2x }{(x-y)(x+y)}= frac{4xy}{ x^{2}- y^{2} }$

Answer 2

спасибо!