Precalculus (10th Edition)

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

Chapter 5 - Exponential and Logarithmic Functions - 5.3 One-to-One Functions; Inverse Functions - 5.3 Assess Your Understanding - Page 282: 74

Answer

$x=6$.

Work Step by Step

$9^{-x+15}=(3^2)^{-x+15}=3^{-2x+30}$, $27^x=(3^3)^x=3^{3x}$ hence the equation becomes: \begin{align*}3^{-2x+30}=3^{3x}.\end{align*} The base is same on the 2 sides on the equation (and it is not $1$ or $-1$), hence they will be equal if the exponents are equal. Hence $-2x+30=3x\\30=5x\\x=6$.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After 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.