Answer
$[-4,1]$
Work Step by Step
Step 1. Factor the left side to get $(x+4)(x-1)\le0$
Step 2. Identify the boundary points as $x=-4,1$ forming three intervals $(-\infty,-4],[-4,1],[1,\infty)$ on a number line.
Step 3. Use test values $x=-5, 0, 2$ for the inequality to get $F, T, F$ (F-False, T-True)
Step 4. The solution is the middle interval $[-4,1]$
