Two firms produce differentiated products. Let P1 and P2 be the prices firm 1 and firm 2 charge and Q1 and Q2 be the demands for firm 1s and firm 2s products, respectively. They satisfy Q1 = 7 3P1 + P2, and Q2=73P2+P1. The total cost of production is C1 = Q1 for firm 1, and C2 = Q2 for firm 2. These two firms set their prices simultaneously (Bertrand Competition). Identify whether these two goods are substitutes or complements. Find the prices of these two firms in a Bertrand equilibrium..