It is an exponential function whose range is all the positive values. This is, for any value of x that exponential function yields a value that is greater than 0. The graph never crosses the x-axis.
When you reflect the function over the x-axis, you flip the graph over x, and you can see that the range of the new fucntion iis all the negative values, this is all the real numbers less than zero.
First lets remove the initial fee 150 is how much she is charging you per hour. If each hour is 55, lets divide 150 by 55. She charged you for 2.7 hours (almost 3) of service
