The weekly marginal cost of producing x pairs of tennis shoes is given by the following function, where C(x) is cost in dollars. 200 C'(X) = 16 + X + 1 If the fixed costs are $4,000 per week, find the cost function. What is the average cost per pair of shoes if 1,000 pairs of shoes are produced each week? . . . The cost function is C(x) =. If 1,000 pairs of shoes are produced each week, the average cost per pair of shoes is $ (Round to the nearest cent as needed.)