Answer
$x=\ln5$ or $x=\ln3$
Work Step by Step
Let $u=e^x$
$e^{2x}-8^x+15=0$
$u^2-8u+15=0$
Factor.
$(u-5)(u-3)=0$
Equate each factor to 0.
$u=5$ or $u=3$
Since $e^x=u$
$e^x=5$ or $e^x=3$
$x=\ln5$ or $x=\ln3$
College Algebra (11th Edition)
by Lial, Margaret L.; Hornsby John; Schneider, David I.; Daniels, Callie
Published by
Pearson
ISBN 10:
0321671791
ISBN 13:
978-0-32167-179-0
Chapter 4 - Section 4.5 - Exponential and Logarithmic Equations - 4.5 Exercises - Page 446: 30
Update this answer!
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.
