Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

Published by Pearson
ISBN 10: 0-32184-874-8
ISBN 13: 978-0-32184-874-1

Chapter 11 - Quadratic Functions and Equations - Mid-Chapter Review - Mixed Review - Page 733: 7

Answer

$x=\pm 2$ or $x=\pm 2i$

Work Step by Step

$ x^{4}=16\qquad$...substitute $x^{2}$ for $u$ so that $x^{4}=u^{2}$. $u^{2}=16$ According to the general principle of square roots: For any real number $k$ and any algebraic expression $x$ : $\text{If }x^{2}=k,\text{ then }x=\sqrt{k}\text{ or }x=-\sqrt{k}$. $u=\pm 4$ Bring back $x^{2}=u$ $x^{2}=4$ or $x^{2}=-4$ $x=\pm 2$ or $x=\pm 2i$
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