If f(x)=2xf(x) = 2xf(x)=2x and g(x)=x+1g(x) = x + 1g(x)=x+1, what is (f+g)(x)(f+g)(x)(f+g)(x)?
3x+13x + 13x+1
2x2+2x2x^2 + 2x2x2+2x
3x23x^23x2
2x2+12x^2 + 12x2+1