ПОЖАЛУЙСТА ПОМОГИТЕ!!!!!!!!!!!!!БАЛЛОВ МНОГО!!!!!!!ВЫДЕЛЕННОЕ!!!!!!!!!!

А)
$\frac{y}{ {(x - y)}^{2} } - \frac{x + y}{ {y}^{2} - xy } = \frac{y}{ {(x - y)}^{2} } - \frac{x + y}{y(y - x)} = \frac{y}{ {(x - y)}^{2} } + \frac{x + y}{y(x - y)} = \frac{ {y}^{2} + (x + y)(x - y) }{y {(x - y)}^{2} } = \frac{ {y}^{2} + {x}^{2} - {y}^{2} }{y {(x - y)}^{2} } = \frac{ {x}^{2} }{y {(x - y)}^{2} }$
б)
$\frac{9p + 63}{ {( - p - 9)}^{2} } - \frac{8}{p + 9} = \frac{9p + 63}{ {(p + 9)}^{2} } - \frac{8}{p + 9} = \frac{9p + 63 - 8(p + 9)}{ {(p + 9)}^{2} } = \frac{9p + 63 - 8p - 72}{ {(p + 9)}^{2} } = \frac{p - 9}{ {(p + 9)}^{2} }$