$fx=\frac{x\left(x+5\right)}{3x-4}\text{ and }x\neq \frac{-3+\sqrt{183}i}{6}\text{ and }x\neq \frac{-\sqrt{183}i-3}{6}$

$\left\{\begin{matrix}\\x=0\text{, }&\text{unconditionally}\\x=\frac{4f+5}{3f-1}\text{, }&f\neq \frac{1}{3}\end{matrix}\right.$

$\left\{\begin{matrix}f\in \mathrm{R}\text{, }&x=0\\f=\frac{x+5}{3x-4}\text{, }&x\neq \frac{4}{3}\end{matrix}\right.$