Question 563568
We have (x+4)(x+9) > 0. What you would do is test certain values of x to see which intervals satisfy. For example, suppose x = -5. Then (-5+4)(-5+9)>0, a false statement. Hence the answer is (infinity, -9) U (-4, infinity).


The other method to do is it note that (x+4)(x+9) is a parabola that opens upward, so the part between the roots -4, -9 would be below the x-axis.