$$\frac{V}{9}=\frac{\partial}{G}$$
$\left\{\begin{matrix}G=\frac{9∂}{V}\text{, }&∂\neq 0\text{ and }V\neq 0\\G\neq 0\text{, }&V=0\text{ and }∂=0\end{matrix}\right.$
$V=\frac{9∂}{G}$
$G\neq 0$
