Answer
$f^{-1}(x)=\frac{1}{3}e^{x/2}$, domain $(-\infty,\infty)$, rang $(0,\infty)$
Work Step by Step
Step 1. Find the inverse: $y=2ln{3x} \longrightarrow x=\frac{1}{3}e^{y/2} \longrightarrow f^{-1}(x)=\frac{1}{3}e^{x/2}$
Steo 2. For $f^{-1}(x)=\frac{1}{3}e^{x/2}$, we can find domain $(-\infty,\infty)$, rang $(0,\infty)$