College Algebra (10th Edition)

Published by Pearson
ISBN 10: 0321979478
ISBN 13: 978-0-32197-947-6

Chapter 1 - Section 1.3 - Complex Numbers; Quadratic Equations in the Complex Number System - 1.3 Assess Your Understanding - Page 111: 8


Option (b)

Work Step by Step

The principal square root is the non-negative root. Thus, the principal square root of $-4$ is: $=\sqrt{-4} \\=\sqrt{4(-1)} \\=\sqrt{2^2(-1)} \\=2\sqrt{-1} \\=2i$ Thus, the answer is $b$.
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