Question

выполните вычитание 3/x+y-3/x-y

Answer 1

$\frac{3}{x+y}-\frac{3}{x-y}=\frac{3*(x-y)-3(x+y)}{(x+y)(x-y)}=$

$=\frac{3x-3y-3x-3y}{(x+y)(x-y)}=\frac{-6y}{x^2-y^2}=-\frac{6y}{x^2-y^2}=\frac{6y}{y^2-x^2}$