### Cournot Duopoly - Reaction Functions

Starting with the reaction functions of duopolists A and B from Problem 4, find the Cournot solution algebraically. Given the reaction function of duopolist A, QA = (12-QB)/2 (1) and the reaction function of duopolist B, QB= (12-QA)/2 (2), find the Cournot solution , that is to find QA and QB by substituting (1) into (2).