Question 1035424
a.  The profit function would be {{{P(x) = R(x) - C(x) = 4x^2-5x-15}}}.

b.The average rate of change in the profit from year 3 to year 5 is {{{(P(5) - P(3))/(5-3) = (P(5) - P(3))/2 = 54/2 = 27}}}, or $27,000,000 per year.