Answer
See below
Work Step by Step
$f(3x^{1/2})=3(3x^{1/2})^{1/2}=(3\times3^{1/2})\times(x^{1/2})^{1/2}=3\sqrt 3x^{1/4}$
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.