Given f(x)=2xf(x) = 2xf(x)=2x and g(x)=x+6g(x) = x + 6g(x)=x+6, what is the composite function (f∘g)(x)(f \circ g)(x)(f∘g)(x)?
2x+62x + 62x+6
2x+122x + 122x+12
x2+6x^2 + 6x2+6
x+8x + 8x+8