Find a formula for the inverse, that is find LaTeX: \displaystyle f^{-1}(x) if LaTeX: \displaystyle f(x)=\frac{9 - 5 x}{5 x + 3} .

LaTeX: \displaystyle f^{-1}(x)=\frac{3 \left(3 - x\right)}{5 \left(x + 1\right)}