Hello everyone.

I have two urgent maths questions related to simplifying and solving algebraic fractions. I will be very gratified if you could pinpoint my mistakes and correct them with clear explanations.

1.$\displaystyle \dfrac{(a-b)^2 +a(a+b) -11b^2}{a^2 -4b^2}$

2.$\displaystyle (\dfrac{-2}{xy})^2$ X $\displaystyle \dfrac{y(y -x)^2}{4} $ X $\displaystyle \dfrac{x^2y^2}{(x^2 -y^2)}$

Here are my workings respectively-

1. $\displaystyle \dfrac{(a-b)^2 +a(a+b) -11b^2}{a^2 -4b^2}$

=$\displaystyle \dfrac{a^2-2ab+b^2+a^2+ab-11b^2}{(a-2b)(a+2b)}$

=$\displaystyle \dfrac{a^2+a^2-2ab+ab+b^2-11b^2}{(a-2b)(a+2b)}$

=$\displaystyle \dfrac{2a^2-ab-10b^2}{(a-2b)(a+2b)}$

=$\displaystyle \dfrac{(-2a+5b)(-a-2b)}{(a-2b)(a+2b)}$ ????

2. $\displaystyle (\dfrac{-2}{xy})^2$ X $\displaystyle \dfrac{y(y -x)^2}{4} $ X $\displaystyle \dfrac{x^2y^2}{(x^2 -y^2)}$

= $\displaystyle \dfrac{-4}{x^2y^2}$ X $\displaystyle \dfrac{y(y^2-2xy+x^2)}{4}$ X $\displaystyle \dfrac{x^2y^2}{(x-y)(x+y}$ ?????