Intermediate Algebra (12th Edition)

Published by Pearson
ISBN 10: 0321969359
ISBN 13: 978-0-32196-935-4

Chapter 8 - Chapter R-8 - Cumulative Review Exercises - Page 579: 21

Answer

$\dfrac{4}{xy^2}$

Work Step by Step

Using the laws of exponents, the given expression, $ \dfrac{(4x^{-2})^2(2y^3)}{8x^{-3}y^5} $, is equivalent to \begin{align*}\require{cancel} & \dfrac{(4^{1(2)}x^{-2(2)})(2y^3)}{8x^{-3}y^5} &(\text{use }(x^my^n)^p=x^{mp}y^{np}) \\\\&= \dfrac{(4^{2}x^{-4})(2y^3)}{8x^{-3}y^5} \\\\&= \dfrac{(16x^{-4})(2y^3)}{8x^{-3}y^5} \\\\&= \dfrac{32x^{-4}y^3}{8x^{-3}y^5} \\\\&= (32\div8)(x^{-4-(-3)}y^{3-5}) &(\text{use }\dfrac{x^m}{x^n}=x^{m-n}) \\&= 4(x^{-4+3}y^{3-5}) \\&= 4(x^{-1}y^{-2}) \\\\&= 4\cdot\dfrac{1}{x}\cdot\dfrac{1}{y^2} &(\text{use }x^{-m}=\dfrac{1}{x^m}) \\\\&= \dfrac{4}{xy^2} .\end{align*} Hence, the expression $ \dfrac{(4x^{-2})^2(2y^3)}{8x^{-3}y^5} $ simplifies to $ \dfrac{4}{xy^2} $.
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