Question

помогите пожалуйста!!!!!! ​

Answer 1

$\dfrac{r^2-36}{r+3}\cdot \dfrac{1}{r^2+6r}-\dfrac{r+6}{r^2-3r}=\dfrac{(r-6)(r+6)}{(r+3)\cdot r\cdot (r+6)}-\dfrac{r+6}{r(r-3)}=\\\\\\=\dfrac{(r-6)(r-3)-(r+6)(r+3)}{r\cdot (r+3)\cdot (r+3)}=\dfrac{r^2-9r+18-(r^2+9r+18)}{r\cdot (r+3)(r-3)}=\\\\\\=\dfrac{-18r}{r\cdot (r+3)(r-3)}=-\dfrac{18}{r^2-9}=\dfrac{18}{9-r^2}$