Answer
See below
Work Step by Step
Demonstrate $f(g(x))$ is true.
Obtain $f(g(x))=f(\frac{x+7}{4})^{1/3}=4((\frac{x+7}{4})^{1/3})^3-7=4\frac{x+4}{4}-7=x+7-7=x$
Since $f(g(x))=x$, the two functions have been verified to be inverse functions.