Chapter 1 - Equations and Inequalities - 1.7 Inequalities - 1.7 Exercises - Page 160: 56

$(-\infty,-1)U(4, \infty)$

Step 1. Identify the boundary points as $x=-1$ and $x=4$ Step 2. Use test points at $x=-2, 0, 5$, the signs of the left side are $+, -, +$ Step 3. The inequality requires positive (two outer regions), thus the solution intervals are $(-\infty,-1)U(4, \infty)$