Functions Modeling Change: A Preparation for Calculus, 5th Edition

Published by Wiley
ISBN 10: 1118583191
ISBN 13: 978-1-11858-319-7

Chapter 5 - Logarithmic Functions - Exercises to Skills for Chapter 5 - Page 232: 43


$x \approx 0.439$

Work Step by Step

Take the natural log of both sides to get $$\ln e^{-5x} = \ln 9$$ Since $\ln a^b=b \ln a$, the equation becomes $$-5x \ln e = -5x = \ln 9$$ Divide both sides by $-5$ to get $$x=\frac{\ln 9}{-5} \approx-0.439$$
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.