Intermediate Algebra (6th Edition)

Published by Pearson
ISBN 10: 0321785045
ISBN 13: 978-0-32178-504-6

Chapter 8 - Section 8.1 - Solving Quadratic Equations by Completing the Square - Exercise Set - Page 485: 71

Answer

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

Work Step by Step

Using the completing the square method, the solutions of the given quadratic equation, $ 2x^2-4x=-3 ,$ is \begin{array}{l}\require{cancel} \dfrac{1}{2}\cdot (2x^2-4x)=(-3)\cdot\dfrac{1}{2} \\\\ x^2-2x=-\dfrac{3}{2} \\\\ x^2-2x+\left( \dfrac{-2}{2} \right)^2=-\dfrac{3}{2}+\left( \dfrac{-2}{2} \right)^2 \\\\ x^2-2x+1=-\dfrac{3}{2}+1 \\\\ x^2-2x+1=-\dfrac{3}{2}+\dfrac{2}{2} \\\\ (x-1)^2=-\dfrac{1}{2} \\\\ x-1=\pm\sqrt{-\dfrac{1}{2}} \\\\ x-1=\pm i\sqrt{\dfrac{1}{2}} \\\\ x-1=\pm i\sqrt{\dfrac{1}{2}\cdot\dfrac{2}{2}} \\\\ x-1=\pm i\sqrt{\dfrac{2}{4}} \\\\ x-1=\pm i\dfrac{\sqrt{2}}{2} \\\\ x=1\pm i\dfrac{\sqrt{2}}{2} \\\\ x=\dfrac{2}{2}\pm i\dfrac{\sqrt{2}}{2} \\\\ x=\dfrac{2\pm i\sqrt{2}}{2} .\end{array} Hence, $ x=\left\{ \dfrac{2-i\sqrt{2}}{2},\dfrac{2+i\sqrt{2}}{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.