Answer
$(gof)(x)$
Work Step by Step
If we analyze $\sqrt{3x}$, we can see it is the square root of $(3x)$, which is $\sqrt{f(x)}$ which is $g(f(x))$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.