The figure above shows the graphs of five exponential 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.

: $f(x) = 2^x.$
: $f(x) = 2^x+1.$
: $f(x) = 2^{x+1}.$
: $f(x) = 2^x-1.$
: $f(x) = 2^{x-1}.$

Hint: Look at $f(0)$ and $f(1)$, and at what happens when x becomes more negative.