Which function grows faster as xxx increases?
f(x)=2xf(x) = 2xf(x)=2x
f(x)=x2f(x) = x^2f(x)=x2
f(x)=x+100f(x) = x + 100f(x)=x+100
f(x)=5f(x) = 5f(x)=5