Find all values of r such that (r - 3)/sqrt(r) = -2*sqrt(r).
\(\frac{r-3}{\sqrt{r}} = -2\times\sqrt{r}\\ r-3 = -2\times \sqrt{r} \times \sqrt{r} = -2 \times r\\ r-3 = -2 \times r\\ 3 \times r = 3\\ r = 1\)