x^2 - 3x -28 ≥ 0
factor
(x-7) (x+4) ≥ 0
x=7 x=-4
we have three regions where the answers can lie
x<-4 between -4 and 7 and x>7
pick a point and see if it works
x=-10
(-10-7) (-10+4) ≥ 0
negative * negative is greater than 0 so this is a solution x< -4
x=0
(0-7) (+4) ≥ 0
negative * positive is less than 0 so this is not a solution
x=10
(10-7) (10+4) ≥ 0
positive * positive is greater than 0 so this is a solution x>7
We have two regions that work
x<-4 and x>7
