Which function represents exponential growth?

f(x) = 3x

f(x) = x^3
f(x) = x + 3
f(x) = 3^x

In the diagram, the ratios of two pairs of corresponding sides are equal to prove that almn - axyz by the sas similarity theorem, it also needs to be shown that x 6 z un z zz un = 2x zləzz lezy