Precalculus (10th Edition)

Published by Pearson
ISBN 10: 0-32197-907-9
ISBN 13: 978-0-32197-907-0

Appendix A - Review - A.10 nth Roots; Rational Exponents - A.10 Assess Your Understanding - Page A88: 43

Answer

$(2x-1)\sqrt[3]{2x}$

Work Step by Step

Simplify each radical (when needed) by factoring the radicand such that one of the factors is a perfect cube: $\sqrt[3]{16x^4}-\sqrt[3]{2x}\\ =\sqrt[3]{8x^3\cdot 2x}-\sqrt[3]{2x}\\ =\sqrt[3]{2^3x^3\cdot 2x}-\sqrt[3]{2x}\\ =\sqrt[3]{(2x)^3\cdot 2x}-\sqrt[3]{2x}$ Use the rule $\sqrt[n]{a\cdot b}=\sqrt[n]{a} \cdot \sqrt[n]{b}$ then simplify: $=\sqrt[3]{(2x)^3}\cdot \sqrt[3]{2x}-\sqrt[3]{2x}$ $=2x\cdot \sqrt[3]{2x}-\sqrt[3]{2x}$ $=2x\sqrt[3]{2x}-\sqrt[3]{2x}$ Factor out $\sqrt[3]{2x}$. $=\sqrt[3]{2x}(2x-1)$ $=(2x-1)\sqrt[3]{2x}$ Hence, the correct answer is $(2x-1)\sqrt[3]{2x}$.
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