The total cost in dollars) of producing x college textbooks is C(x) = 43x +72,000. (a) What are the fixed costs? (b) What is the marginal cost per book? (C) What is the total cost of producing 1500 books? 33.000 books? (d) What is the average cost when 1500 books are produced? when 33.000 books are produced? (a) The fixed costs are $ (Simplify your answer.)