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