Identify the exponential growth function from the list below.
f(x)=5(0.8)xf(x) = 5(0.8)^xf(x)=5(0.8)x
f(x)=3x2f(x) = 3x^2f(x)=3x2
f(x)=2(1.2)xf(x) = 2(1.2)^xf(x)=2(1.2)x
f(x)=4−0.5xf(x) = 4 - 0.5xf(x)=4−0.5x