Precalculus (6th Edition)

Published by Pearson
ISBN 10: 013421742X
ISBN 13: 978-0-13421-742-0

Chapter 1 - Equations and Inequalities - 1.7 Inequalities - 1.7 Exercises - Page 159: 45

Answer

$$\color{blue}{[-2,3]}$$

Work Step by Step

$\bf\text{First, simplify and rewrite with all terms on the left side.}$ $x(x-1)\leq6$ $x^2-x\leq6$ $x^2-x-6\leq0$ $\bf\text{Factoring the trinomial gives us:}$ $x=-2$ or $x=3$ $\bf\text{Which gives us three intervals:}$ $\bf(-\infty,-2]$ $\bf[-2,3]$ $\bf[3,\infty)$ $\bf\text{Using test values we can test each interval in the formula}$ For the interval $\bf(-\infty,-2]$, we can use $-3$ as our test value $(-3)^2-(-3)-6\leq0$ $9+3-6\leq0$ $6\leq0$ which is untrue so this interval is $\bf\text{not valid}$ For the interval $\bf[-2,3]$ we can use $1$ as our test value $(1)^2-(1)-6\leq0$ $1-7\leq0$ $-6\leq0$ which is true so this interval is $\bf\text{valid}$ For the interval $\bf[3,\infty)$, we can use $4$ as our test value $(4)^2-(4)-6\leq0$ $16-10\leq0$ $6\leq0$ which is untrue so this interval is $\bf\text{not valid}$ Therefore the solution is $\color{blue}{[-2,3]}$
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.