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: 40

Answer

$14+29i$

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: $=4(5+6i) + i(5+6i) \\=4(5) + 4(6i) + i(5) + i(6i) \\=20+ 24i+5i+6i^2 \\=20 + 29i+6i^2$ Use rule (2) above to obtain: $=20+29i+6(-1) \\=20+29i+(-6) \\=20+29i-6 \\=14+29i$
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