$\left\{\begin{matrix}Q=-\frac{xP^{2}-4x+3}{P+1}\text{, }&P\neq -1\\Q\in \mathrm{C}\text{, }&x=1\text{ and }P=-1\end{matrix}\right.$

$\left\{\begin{matrix}Q=-\frac{xP^{2}-4x+3}{P+1}\text{, }&P\neq -1\\Q\in \mathrm{R}\text{, }&P=-1\text{ and }x=1\end{matrix}\right.$

$\left\{\begin{matrix}P=\frac{\sqrt{16x^{2}-4Qx-12x+Q^{2}}-Q}{2x}\text{; }P=-\frac{\sqrt{16x^{2}-4Qx-12x+Q^{2}}+Q}{2x}\text{, }&x\neq 0\\P=\frac{-Q-3}{Q}\text{, }&x=0\text{ and }Q\neq 0\end{matrix}\right.$

$\left\{\begin{matrix}P=\frac{\sqrt{16x^{2}-4Qx-12x+Q^{2}}-Q}{2x}\text{; }P=-\frac{\sqrt{16x^{2}-4Qx-12x+Q^{2}}+Q}{2x}\text{, }&x\neq 0\text{ and }\left(Q\leq -1\text{ or }Q\geq 3\text{ or }x\leq -\frac{\sqrt{144+96Q-48Q^{2}}}{32}+\frac{Q}{8}+\frac{3}{8}\text{ or }x\geq \frac{\sqrt{144+96Q-48Q^{2}}}{32}+\frac{Q}{8}+\frac{3}{8}\right)\\P=\frac{-Q-3}{Q}\text{, }&x=0\text{ and }Q\neq 0\end{matrix}\right.$