Answer
$[-5,2]$ or $\{x|-5\le x\le2 \}$.
Work Step by Step
Step 1. $x^2+3x-10\le0 \longrightarrow (x+5)(x-2)\le0$.
Step 2. Identify boundary points $x=-5,2$ and form intervals $(-\infty,-5],[-5,2],[2,\infty)$.
Step 3. Choose test values $x=-6,0,3$ to test the inequality and get results $False,\ True,\ False$.
Step 4. Thus we have the solution $[-5,2]$ or $\{x|-5\le x\le2 \}$.
