posted by vince on .
solve the inequality,express using interval notation
First factor it and rewrite as
x (x-7)(x+2) > 0
The function crosses the y axis at x = -2, x=0 and x=7
When x<-2 all three factors are negative, so the function is <0 there
The -2<x<0, two factors are negative and one is postive, so the inequality is satisfied.
Cosider also the regions 0<x<7 and x>7 and figure out if the fucntiuon is postive or negative there.