Maximize profits for a monopolistic firm producing two related goods, i.e., P = f(Q, Q) when the goods are substitutes and the demand and total cost functions are P = 80-5Q-2Q2 P = 50-Q3Q2 TC = 3Q + QQ2+2Q By using (a) Cramer's rule for the first-order condition, and (b) the Hessian for the second-order condition.