Question

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

Answer 1

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.