Chapter R - Algebra Reference - R.5 Inequalities - R.5 Exercises - Page R-21: 32

$2k^2-7k-15\leq0$ $(2k+3)(k-5)\leq0$ $\frac{-3}{2}\leq k\leq5$

Step 1: Factorize inequality (trinomial) Step 2: The roots of the quadratic inequality is $k=\frac{-3}{2}$ and $ k=5$ Step 3: The quadratic inequality function is smaller than and equal to $0$ for $\frac{-3}{2}\leq k\leq5$