Question

помогите с яклассом
на фотке

Answer 1

$(\frac{r^2-3r+9}{9r^2-1}\cdot \frac{3r^2+r}{r^3+27}-\frac{r+3}{3r^2-r}):\frac{5}{r^2+3r}-\frac{5r+16}{5-15r} =$

$=(\frac{r^2-3r+9}{(3r-1)(3r+1)} \cdot \frac{r(3r+1)}{(r+3)(r^2-3r+9)}-\frac{r+3}{r(3r-1)})\cdot \frac{r(r+3)}{5}+\frac{5r+16}{15r-5} =$

$=(\frac{1}{3r-1} \cdot \frac{r}{r+3}-\frac{r+3}{r(3r-1)})\cdot \frac{r(r+3)}{5}+\frac{5r+16}{15r-5} =$

$=(\frac{r^2-(r+3)(r+3)}{r(3r-1)(r+3)})\cdot \frac{r(r+3)}{5}+\frac{5r+16}{15r-5} =$

$=\frac{r^2-r^2-6r-9}{r(3r-1)(r+3)}\cdot \frac{r(r+3)}{5}+\frac{5r+16}{15r-5} =$

$=\frac{-6r-9}{3r-1}\cdot \frac{1}{5}+\frac{5r+16}{5(3r-1)} =$

$=\frac{-6r-9+5r+16}{5(3r-1)} =\frac{7-r}{5(3r-1)}$