Algebra 2 Common Core

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

Chapter 7 - Exponential and Logarithmic Functions - Chapter Test - Page 491: 33

Answer

$x\approx -16.0577$ and $x\approx 17.0577$

Work Step by Step

Square the binomial to obtain \begin{align*} \ln{\left(4x^2-4x+1\right)}&=7\\\\ \end{align*} Recall: $$\ln{x}=n \longrightarrow e^n=x$$ Use the definition above to obtain: \begin{align*} e^7&=4x^2-4x+1\\\\ 0&=4x^2-4x+1-e^7 \end{align*} Recall: The quadratic equation $ax^2+bx+c=0$ can be solved using the Quadratic Formula: $$x=\dfrac{-b\pm \sqrt{b^2-4ac}}{2a}$$ WIth $a=4, b=-4,$ and $c=1-e^7$, solve the equation using the Quadratic Formula to obtain: \begin{align*} x&=\dfrac{-(-4)\pm\sqrt{(-4)^2-4(4)(1-e^7)}}{2(4)}\\\\ x&=\dfrac{4\pm\sqrt{16-16(1-e^7)}}{8}\\\\ x&=\dfrac{4\pm 132.4618078}{8}\\\\ x_1&=\dfrac{4-132.4618078}{8}\approx -16.0577\\\\ x_2&=\dfrac{4+132.4618078}{8}\approx 17.0577 \end{align*}
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.