An exponential function is graphed for all real numbers. This includes which of the following sets of numbers?

In addition to linear, quadratic, rational, and radical functions, there are exponential functions. Exponential functions have the form f(x) = bx, where b > 0 and b ≠ 1. Just as in any exponential expression, b is called the base and x is called the exponent. An example of an exponential function is the growth of bacteria. Some bacteria double every hour. If you start with 1 bacterium and it doubles every hour, you will have 2x bacteria after x hours. This can be written as f(x) = 2x. Before you start,   f(0) = 20 = 1After 1 hour           f(1) = 21 = 2In 2 hours              f(2) = 22 = 4In 3 hours              f(3) = 23 = 8and so on.  With the definition f(x) = bx and the restrictions that b > 0 and that b ≠ 1, the domain of an exponential function is the set of all real numbers. The range is the set of all positive real numbers. The following graph shows f(x) = 2x.