Answer
(a) $ f^{-1}(x) =\frac{1}{3}x+\frac{4}{3}$
(b) see graph
(c) $f(x)$ domain $(-\infty,\infty)$ and range $(-\infty,\infty)$, $f^{-1}(x)$ domain $(-\infty,\infty)$ and range $(-\infty,\infty)$,
Work Step by Step
(a) This function $f(x)=3x-4$ is one-to-one. Find the inverse as the following: $y=3x-4\longrightarrow x=\frac{y+4}{3}\longrightarrow f^{-1}(x)=\frac{x+4}{3}=\frac{1}{3}x+\frac{4}{3}$
(b) see graph
(c) $f(x)$ domain $(-\infty,\infty)$ and range $(-\infty,\infty)$, $f^{-1}(x)$ domain $(-\infty,\infty)$ and range $(-\infty,\infty)$,