$$\frac{x+y}{x^{2}-2xy+y^{2}}-\frac{x-2y}{x^{2}-y^{2}}$$
$\frac{y\left(5x-y\right)}{\left(x+y\right)\left(x-y\right)^{2}}$
$-\frac{y^{2}-5xy}{\left(x+y\right)\left(y-x\right)^{2}}$
