Answer
$$\frac{1}{4}\sqrt{4x^2+9}+c .$$
Work Step by Step
Let $u=4x^2+9$, then $du=8xdx$. Now, we have
$$\int \frac{xdx}{\sqrt{4x^2+9}}=\frac{1}{8}\int \frac{du}{\sqrt u}=\frac{1}{8} \frac{\sqrt u}{1/2}+c\\
=\frac{1}{4}\sqrt{4x^2+9}+c .$$
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.