College Algebra (6th Edition)

Published by Pearson
ISBN 10: 0-32178-228-3
ISBN 13: 978-0-32178-228-1

Chapter 4 - Summary, Review, and Test - Cumulative Review Exercises (Chapters 1-4) - Page 514: 5

Answer

$x=3$

Work Step by Step

Combine like terms and rewrite using the definition of log. Then factor the side with $x$ to solve. $-7$ is not part of the domain, so $3$ is the answer. $\log_2(x+5)+\log_2(x-1)=4$ $\log_2(x+5)(x-1)=4$ $16=x^2+4x-5$ $x^2+4x-21=0$ $(x+7)(x-3)=0$ $x=-7, x=3$ $x=3$
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