$i\sqrt 7 $
Work Step by Step
To express in terms of $i$ simply divide the number under the radical by -1 and write i as a multiplier. $\sqrt 7$ is not reducible. Thus the answer is $\sqrt 7$i.
You can help us out by revising, improving and updating this answer.Update this answer
After 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.