#### Answer

Sum

#### Work Step by Step

The sum of the first n terms of an arithmetic sequence can be calculated as:
$\frac{n}{2}(a_1+a_n)$
Here:
$\frac{4}{2}(5+11)$

Published by
Pearson

ISBN 10:
0-32184-874-8

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

Sum

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.