Помогите упростить выражение:

1) (1 / x-y - 1 / x+y) · x²-y² / y²

2) (1 / x²+1 / y²+1 / x+y · 2x+2y / xy) · x²y² / x²-y²

(y/x-y + x/x+y) : (1/x^2 + 1 / y^2) - y^4 / x^2-y^2 = (y (x+y) + x (x-y) / (x-y) (x+y)) / (x^2+y^2/x^2y^2) - y^4 / (x-y) (x+y) = (xy+y^2+x^2-xy / (x-y) (x+y)) / (x^2+y^2/x^2y^2) - y^4 (x-y) (x+y) = (x^2+y^2 / (x-y) (x+y)) / (x^2+y^2/x^2y^2) - y^4 (x-y) (x+y) = (x^2+y^2) (x^2y^2) / (x^2+y^2) (x-y) (x+y) - y^4 / (x-y) (x+y) = x^2y^2 / (x-y) (x+y) - y^4 / (x-y) (x+y) = x^2y^2-y^4 / (x-y) (x+y) = y^2 (x^2-y^2) / (x-y) (x+y) = y^2 (x-y) (x+y) / (x-y) (x+y) = y^2