You have the following function:
Take into account that the average rate of change is given by the following formula:
where x1 and x2 are the limits of a given interval.
In this case, you have x1 = 0 and x2 = 9. Replace these values to calculate f(0) and f(9):
Next, replace the previous results into the formula for m:
Hence, the average rate of change is 14