8. Let f (t) be the number of tons of ozone-layer damaging Freon 22 produce in year t in developing countries, where t = 0 represent the year 2000. 700 600 500 300 200 100 6 7 8 9 10 a. Use the graph to estimate the average rate of change of f(t) with respect to t over the interval [0, 10] and interpret the results. b. Over which 2-year period(s) was the average rate of change of Freon Production the greatest