Appendix A - Equations and Inequalities - Page 421: 90

$-12$ $\leq$ $x$ $\leq$ $6$ The equivalent interval notation is $[-12, 6]$.

$-5$ $\leq$ $\frac{x - 3}{3}$ $\leq$ $1$ $-5 * 3$ $\leq$ $x - 3$ $\leq$ $1 * 3$ $-15 + 3$ $\leq$ $x$ $\leq$ $3 + 3$ $-12$ $\leq$ $x$ $\leq$ $6$ The equivalent interval notation is $[-12, 6]$.