## Precalculus: Mathematics for Calculus, 7th Edition

$x^{2}$ $\lt$ 4 $x^{2}$ - 4 $\lt$ 0 (x-2)(x+2) $\lt$ 0 Factors are zero when x=+or-2, endpoints don't satisfy the inequality, plug in values from intervals to decide which of them satisfy the inequality.