Помагите упростить выражение. ......

Решите задачу:

$(\frac{2}{2x+y}- \frac{1}{2x-y}- \frac{3y}{y^2-4x^2})*( \frac{y^2}{8x^2}- \frac{1}{2})=( \frac{2(2x-y)-(2x+y)}{4x^2-y^2}+ \frac{3y}{4x^2-y^2})* \\ ( \frac{y^2}{8x^2}- \frac{1}{2})= \frac{4x-2y-2x-y+3y}{4x^2-y^2}*( \frac{y^2}{8x^2}- \frac{1}{2})= \frac{2xy^2}{(4x^2-y^2)8x^2}- \frac{2x}{2(4x^2-y^2}= \\ \frac{y^2}{4x(4x^2-y^2)}- \frac{2x}{2(4x^2-y^2)}= \frac{y^2-2x*2x}{4x(4x^2-y^2}=- \frac{4x^2-y^2}{4x(4x^2-y^2)}=- \frac{1}{4x}$