If f(x)=x+3f(x) = x + 3f(x)=x+3 and g(x)=x−3g(x) = x - 3g(x)=x−3, what is (f+g)(x)(f+g)(x)(f+g)(x)?
2x2x2x
666
x2−9x^2 - 9x2−9
000