In the following duopoly model, the firms operate in a market where their products are not completely identical but can be considered substitutes for each other. If Firms 1 and 2 choose unit sales prices p and p2, respectively, the quantity that consumers demand from Firm 1 is 91(P.P2) a P+ bp2 and from Firm 2 is 92(P1 P2) = a-p2 + bp where 0 < b < 2 reflects the extent to which Firm i's product is a substitute for Firm j's. The total cost to Firm i for producing q, units is cq, where c