Big Ideas Math - Algebra 1, A Common Core Curriculum

Published by Big Ideas Learning LLC
ISBN 10: 978-1-60840-838-2
ISBN 13: 978-1-60840-838-2

Chapter 2 - Solving Linear Inequalities - 2.5 - Solving Compound Inequalities - Exercises - Page 86: 21

Answer

The second step is wrong. The correct solution is $-\frac{1}{2}\gt x \gt -3$. The correct graph is shown below.

Work Step by Step

The given inequality is $\Rightarrow 4\lt -2x+3 \lt 9$ Subtract $3$ from each expression. $\Rightarrow 4-3\lt -2x+3-3 \lt 9-3$ Simplify. $\Rightarrow 1\lt -2x \lt 6$ Divide each side by $-2$. Reverse the inequality symbol. $\Rightarrow \frac{1}{-2}\gt \frac{-2x}{-2} \gt \frac{6}{-2}$ Simplify. $\Rightarrow -\frac{1}{2}\gt x \gt -3$ Hence, the second step is wrong. The correct solution is $-\frac{1}{2}\gt x \gt -3$.
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