Algebra 2

Solve: f (x) = x^2-9

This problem is a difference of squares. So to solve this you want to factor it out so you get two numbers that multiple to - 9 and add to 0. That would be - 3 and 3

f (x) = (x-3) (x+3)

So your solution when you set f (x) to 0 would be - 3 and 3.