#### Answer

-9i

#### 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 81$$=-9$. Thus the answer is -9i.

Published by
Pearson

ISBN 10:
0-32184-874-8

ISBN 13:
978-0-32184-874-1

-9i

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.