Algebra 2 (1st Edition)

Published by McDougal Littell
ISBN 10: 0618595414
ISBN 13: 978-0-61859-541-9

Chapter 4 Quadratic Functions and Factoring - 4.7 Complete the Square - Guided Practice for Examples 3, 4, and 5 - Page 286: 10


The solutions are $-2+\sqrt{10}$ and $-2-\sqrt{10}$.

Work Step by Step

$ 3x^{2}+12x-18=0\qquad$ ... write left side in the form $x^{2}+bx$ (add $18$ to each side). $ 3x^{2}+12x=18\qquad$ ...divide each term with $3$. $ x^{2}+4x=6\qquad$ ...square half the coefficient of $x$. $(\displaystyle \frac{4}{2})^{2}=2^{2}=4\qquad$ ...add $4$ to each side of the expression $ x^{2}+4x+4=6+4\qquad$ ...simplify. $ x^{2}+4x+4=10\qquad$ ... write left side as a binomial squared. $(x+2)^{2}=10\qquad$ ...take square roots of each side. $ x+2=\pm\sqrt{10}\qquad$ ...add $-2$ to each side $ x+2-2=\pm\sqrt{10}-2\qquad$ ...simplify. $x=-2\pm\sqrt{10}$
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.