f(x) = [tex]5^{x}[/tex]
note the range is {1, 5, 25, 125 } which can be expressed as
{ [tex]5^{0}[/tex], [tex]5^{1}[/tex], [tex]5^{2}[/tex], [tex]5^{3}[/tex] }
the exponents being the domain { 0, 1, 2, 3 }
thus f(x) = [tex]5^{x}[/tex] an exponential function