Question

Разность алгеброических дробей ​

Answer 1

$\frac{y}{(y+9)^{2}} -\frac{y}{y^{2}-81} =\frac{y}{(y+9)^{2}} -\frac{y}{(y-9)(y+9)} =\frac{y(y-9)}{(y-9)(y+9)^{2}} -\frac{y(y+9)}{(y-9)(y+9)^{2}} =\frac{y^{2}-9y-y^{2}-9y}{(y-9)(y+9)^{2}} =\\\\=\frac{-18y}{(y-9)(y+9)^{2}}$

$B=(y+9)(y-9)(y+9)$