College Algebra (11th Edition)

Published by Pearson
ISBN 10: 0321671791
ISBN 13: 978-0-32167-179-0

Chapter 1 - Review Exercises - Page 163: 45


$x=\left\{ \dfrac{\sqrt{5}-3}{2},\dfrac{\sqrt{5}+3}{2} \right\}$

Work Step by Step

$\bf{\text{Solution Outline:}}$ To solve the given equation, $ x^2-\sqrt{5}x-1=0 ,$ use the Quadratic Formula. $\bf{\text{Solution Details:}}$ In the equation above, $a= 1 ,$ $b= -\sqrt{5} ,$ and $c= -1 .$ Using the Quadratic Formula which is given by $x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a},$ then \begin{array}{l}\require{cancel} x=\dfrac{-(-\sqrt{5})\pm\sqrt{(-\sqrt{5})^2-4(1)(-1)}}{2(1)} \\\\ x=\dfrac{\sqrt{5}\pm\sqrt{5+4}}{2} \\\\ x=\dfrac{\sqrt{5}\pm\sqrt{9}}{2} \\\\ x=\dfrac{\sqrt{5}\pm3}{2} .\end{array} The solutions are $ x=\left\{ \dfrac{\sqrt{5}-3}{2},\dfrac{\sqrt{5}+3}{2} \right\} .$
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.