$$C=(4w-5)(2\ cw-8)$$
$\left\{\begin{matrix}c=-\frac{32w+C-40}{2w\left(5-4w\right)}\text{, }&w\neq \frac{5}{4}\text{ and }w\neq 0\\c\in \mathrm{R}\text{, }&\left(C=40\text{ and }w=0\right)\text{ or }\left(C=0\text{ and }w=\frac{5}{4}\right)\end{matrix}\right.$
$C=2\left(4w-5\right)\left(cw-4\right)$
