The demand and supply functions of two related goods are given by
Qd1 = 40 - 5P1 + 6P2
Qs1 = -50 + 4 P1
Qd2 = 120 + 3P1 - 4 P2
Qs2 = -30 + 3P2
(a) What is the relationship between good one and good two?
(b) Find the equilibrium prices and quantities.