$\left\{\begin{matrix}a=-\frac{\sqrt{1-6b-3by}-1}{3\left(y+2\right)}\text{; }a=\frac{\sqrt{1-6b-3by}+1}{3\left(y+2\right)}\text{, }&y\neq -2\\a=\frac{b}{2}\text{, }&y=-2\\a\in \mathrm{C}\text{, }&b=0\end{matrix}\right.$

$\left\{\begin{matrix}a=-\frac{\sqrt{1-6b-3by}-1}{3\left(y+2\right)}\text{; }a=\frac{\sqrt{1-6b-3by}+1}{3\left(y+2\right)}\text{, }&\left(y<-2\text{ or }b\leq \frac{1}{3\left(y+2\right)}\right)\text{ and }\left(b\leq \text{Indeterminate}\text{ or }y\neq -2\right)\text{ and }\left(y>-2\text{ or }\left(y\neq -2\text{ and }b\geq \frac{1}{3\left(y+2\right)}\right)\right)\\a=\frac{b}{2}\text{, }&y=-2\\a\in \mathrm{R}\text{, }&b=0\end{matrix}\right.$

$b=a\left(2-6a-3ay\right)$
$b=0$