The weekly marginal cost of producing x pairs of tennis shoes is given by the following function, where C(x) is cost in dollars. 500 C' (x) = 10+ - x +1 If the fixed costs are $3,000 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.)