1. The demand and supply functions of three related goods are given by
Qd1 = 60 - 5P1 + 2 P2 - 3P3
Qs1 = -10 + 4 P1
Qd2 = 70 + 4 P1 - 4 P2 + 2 P3
Qs2 = -20 + 2 P2
Qd3 = 50 - 2 P1 + 4 P2 - 2 P3
Qs3 = -70 + 5P3
Write the system in matrix form and find the equilibrium prices and quantities.