Suppose you are given the following demand and total cost functions for a firm that produces video games: Q_(d)=120-2P TC=2Q² Let quantity be in millions of units. Use this information to answer th... a. What is the profit-maximizing price and quantity? b. Calculate the marginal revenue for the firm. c. Determine the break-even quantity for the firm. d. Find the average variable cost for producing 60 million units.