Answer:
Step-by-step explanation:
x^2 - 9 = 0
This is a perfect square, meaning that you would take the two factors but one would be negative while the other would be positive:
Factoring this would result in
(x - 3) (x + 3) --> If you FOIL that back you get x^2 - 9
Now set those equal to 0
x - 3 = 0 --> x = 3
x + 3 = 0 --> x = -3
So, x = 3 or -3
