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: 48

Answer

$20$

Work Step by Step

RECALL: (1) $(a+b)(a-b) = a^2-b^2$ (2) $i^2=-1$ Use rule (1) above with $a=-4$ and $b=2i$ to obtain: $=(-4)^2 - (2i)^2 \\=16 - 4i^2$ Use rule (2) above to obtain: $=16 - 4(-1) \\=16-(-4) \\=16+4 \\=20$
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