The figure above shows the graphs of five functions, listed below. Match the functions with the colors, using b for blue, r for red, g for green, p for purple, and y for yellow.

: $f(x) = x.$
: $f(x) = e^x.$
: $f(x) = 5^x.$
: $f(x) = \hbox{ln} (x).$
: $f(x) = \hbox{log}_5 (x).$

Hint: Logarithms are the inverses of the exponential functions.