$\left\{\begin{matrix}c<0\text{, }&a\neq 0\text{ and }b<0\\c>0\text{, }&a\neq 0\text{ and }b>0\end{matrix}\right.$

$\left\{\begin{matrix}b<0\text{, }&a\neq 0\text{ and }c<0\\b>0\text{, }&a\neq 0\text{ and }c>0\end{matrix}\right.$