Precalculus: Mathematics for Calculus, 7th Edition

(-1,2) $\cup$ (5,$\infty$)
(x-5)(x-2)(x+1) $\gt$ 0 Factors are zero when x=-1, x=2 or x=5, these divide the number line into 4 intervals, endpoints don't satisfy the inequality , plug in values from intervals to decide which of them satisfy the inequality.