Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 7 - Section 7.7 - Complex Numbers - Exercise Set: 39

Answer

$7+19i$

Work Step by Step

RECALL: (1) $(a+b)(c+d) \\= a(c+d) + b(c+d) \\=ac+ad + bc + bd$ (2) $i^2=-1$ Use rule (1) above to obtain: $=3(4+5i) + i(4+5i) \\=3(4) + 3(5i) + i(4) + i(5i) \\=12+ 15i+4i+5i^2 \\=12 + 19i+5i^2$ Use rule (2) above to obtain: $=12+19i+5(-1) \\=12+19i+(-5) \\=12+19i-5 \\=7+19i$
Update this answer!

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.