College Algebra (6th Edition)

Published by Pearson
ISBN 10: 0-32178-228-3
ISBN 13: 978-0-32178-228-1

Chapter 5 - Systems of Equations and Inequalities - Exercise Set 5.4 - Page 561: 80

Answer

$x=10^4, y=5$

Work Step by Step

We are given the system: $\begin{cases} \log x^2=y+3\\ \log x=y-1 \end{cases}$ We use the addition method. Multiply Equation 2 by -1 and add it to Equation 1. $\log x^2 - \log x=4$ Using the Quotient rule of logarithmic property, $\log b -\log c = \log \frac{b}{c}$, we can simplify the equation as follows. $\log \frac{x^2}{x}=4,\\ \log x =4$ Using the Inverse of exponent rule of logarithmic property,$b^{\log_{b}a}=a$. by raising both sides of the equation to the power of $10$, we can get an answer for $x$. $10^{\log x}=10^4,\\ x=10^4$. back substituting $x$ into the original Equation we can get answer for $y$. $\log 10^4=y-1,\\ 4 \log 10=y-1,\\ y=5$. Therefore, the answer is: $x=10^4, y=5$
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.