Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 1 - Section 1.6 - Complex Numbers - 1.6 Exercises: 36


$(3-7i)^{2}$ = $-40-42i$

Work Step by Step

1. $(3-7i)^{2}$ 2. Multiply $(3-7i)\times(3-7i)$ (use the FOIL method to distribute the First, Outer, Inner, and Last terms): $9-21i-21i+49i^{2}$ 3. Combine like terms: $9-42i+49i^{2}$ 4. Change $49i^{2}$ to -49 because $i^{2} = -1$ and $49\times-1 = -49$ : $9-42i-49$ 5. Combine like terms:$-40-42i$
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