Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 5 - Section 5.7 - Polynomial Equations and Their Applications - Exercise Set - Page 394: 98

Answer

$x=-2$; $x=0.5$; $x=3$;

Work Step by Step

We use a graphing calculator to graph the function $y=2x^3-3x^2-11x+6$. From the graph we notice that the $x$-intercepts are: $$\begin{align*} x_1&=-2\\ x_2&=0.5\\ x_3&=3. \end{align*}$$ We check if the values $x_1$, $x_2$ and $x_3$ check the equation $2x^3-3x^2-11x+6=0$: $$\begin{align*} x_1&=-2\\ 2(-2)^3-3(-2)^2-11(-2)+6&\stackrel{?}{=}0\\ -16-12+22+6&\stackrel{?}{=}0\\ 0&=0\checkmark\\\\ x_2&=0.5\\ 2(0.5)^3-3(0.5)^2-11(0.5)+6&\stackrel{?}{=}0\\ 0.25-0.75-5.5+6&\stackrel{?}{=}0\\ 0&=0\checkmark\\\\ x_3&=3\\ 2(3^3)-3(3^2)-11(3)+6&\stackrel{?}{=}0\\ 54-27-33+6&\stackrel{?}{=}0\\ 0&=0\checkmark \end{align*}$$ Therefore the solutions of the equation are $-2$, $0.5$ and $3$.
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.