The Tip Top Tennis Balls manufacturing company makes and sells tennis balls. The revenue (in dollars) that the company receives in selling x cases (12 cans per case, three balls per can) of tennis balls in one week is given by The cost (in dollars) is given by All of the following questions refer to a one-week period, and only full cases of balls are sold. Write an equation for the profit P the company makes in producing and selling x cases. (Remember the profit = revenue – cost.) How many tennis balls need to produced and sold for the profit to be greater than zero? Choose the correct answer.