$\left\{\begin{matrix}h=-\frac{b}{3x}\text{, }&x\neq 0\\h\in \mathrm{C}\text{, }&b=0\text{ and }x=0\end{matrix}\right.$

$b=-3hx$

$\left\{\begin{matrix}h=-\frac{b}{3x}\text{, }&x\neq 0\\h\in \mathrm{R}\text{, }&b=0\text{ and }x=0\end{matrix}\right.$