Упростите выражение 1 и 3 пожалуйста

1)
$(\frac{x^2-y^2}{xy}-\frac{1}{x+y}(\frac{x^2}{y}-\frac{y^2}{x})):\frac{x-y}{x}=(\frac{(x+y)(x-y)}{xy}-\frac{1}{x+y}*\frac{x^3-y^3}{xy})*\frac{x}{x-y}= \\ =\frac{(x+y)(x-y)}{xy}*\frac{x}{x-y}-\frac{1}{x+y}*\frac{x^3-y^3}{xy}*\frac{x}{x-y}=\frac{x+y}{y}-\frac{1}{x+y}*\frac{x^2+xy+y^2}{y}= \\ =\frac{(x+y)^2}{y(x+y)}-\frac{x^2+xy+y^2}{y(x+y)}=\frac{x^2+2xy+y^2-x^2-xy-y^2}{y(x+y)}=\frac{x}{x+y}$
3)
$(\frac{1}{a^3}+\frac{1}{b^3})*(\frac{a(b-a)}{a^2-ab+b^2}+1)=\frac{a^3+b^3}{a^3b^3}*(\frac{ab-a^2}{a^2-ab+b^2}+\frac{a^2-ab+b^2}{a^2-ab+b^2})= \\ =\frac{(a+b)(a^2-ab+b^2)}{a^3b^3}*\frac{ab-a^2+a^2-ab+b^2}{a^2-ab+b^2}=\frac{(a+b)(a^2-ab+b^2)}{a^3b^3}*\frac{b^2}{a^2-ab+b^2}= \\ =\frac{a+b}{a^3b}$