Algebra 2 Common Core

Published by Prentice Hall
ISBN 10: 0133186024
ISBN 13: 978-0-13318-602-4

Chapter 7 - Exponential and Logarithmic Functions - 7-5 Exponential and Logarithmic Equations - Practice and Problem-Solving Exercises - Page 475: 79

Answer

$x=5$ or $x=-2$

Work Step by Step

Recall the definition of a logarithm (pg. 451): $\log_{b}{x}=y$ iff $b^y=x$ Applying this definition, we get: $7^2=(2x-3)^2$ $49=(2x-3)^2$ $\pm \sqrt{49}=2x-3$ $\pm 7=2x-3$ $\pm 7+3=2x$ $\dfrac{\pm 7+3}{2}=x$ $x=\frac{7+3}{2}=5$ or $x=\frac{-7+3}{2}=-2$ We confirm that the answers work: $\log_7 (2\cdot5-3)^2=2$ $\log_7 (10-3)^2=2$ $\log_7 (7)^2=2$ $\log_7 (7)^2=2$ $2=2$ $\log_7 [2\cdot (-2)-3]^2=2$ $\log_7 (-4-3)^2=2$ $\log_7 (-7)^2=2$ $\log_7 7^2=2$ $2=2$
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.