7. The monthly profit function for a boat manufacturer in Phoenix, Arizona is P(x) = -- (x-13)2 +21, 3 where x is the number of boats built each month and P is the profit in thousands of dollars per month. (a) How much profit does the company make if 19 boats are completed in one month? (b) Identify all possible number of boat(s) made in one month that result in the company losing money. (c) How many boats should be made each month to maximize the monthly profits for the company