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 473: 42

Answer

$x=5$

Work Step by Step

Recall the power property of logarithms (pg. 462): $\log_b{m^n}=n\log_b{m}$ Applying this property, we get: $\log x^2+\log 4=2$ Next, recall the product property of logarithms (pg. 462): $\log_b{mn}=\log_b{m}+\log_b{n}$ Applying this property to our equation, we get: $\log_{10} 4x^2=2$ Now, recall the definition of a logarithm (pg. 451): $\log_{b}{x}=y$ iff $b^y=x$ Applying this definition to our equation (with $b=10, y=2, x=4x^2$), we get: $10^{2}=4x^2$ $100/4=x^2$ $25=x^2$ $x=\sqrt{25}$ $x=5$ We confirm that the answer works: $2\log 5+\log 4=2$ $\log 5^2+\log 4=2$ $\log{(5^2\cdot4)}=2$ $\log{100}=2$ $\log{10^2}=2$ $2=2$
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.