$\left\{\begin{matrix}M=\frac{30-4P-q}{RP^{2}}\text{, }&R\neq 0\text{ and }P\neq 0\\M\in \mathrm{C}\text{, }&\left(q=30\text{ and }P=0\right)\text{ or }\left(q=30-4P\text{ and }R=0\right)\end{matrix}\right.$

$\left\{\begin{matrix}M=\frac{30-4P-q}{RP^{2}}\text{, }&R\neq 0\text{ and }P\neq 0\\M\in \mathrm{R}\text{, }&\left(q=30\text{ and }P=0\right)\text{ or }\left(q=30-4P\text{ and }R=0\right)\end{matrix}\right.$

$\left\{\begin{matrix}P=-\frac{\sqrt{4+30MR-MRq}+2}{MR}\text{; }P=-\frac{-\sqrt{4+30MR-MRq}+2}{MR}\text{, }&R\neq 0\text{ and }M\neq 0\\P=\frac{30-q}{4}\text{, }&R=0\text{ or }M=0\end{matrix}\right.$