The market demand curve for a good is given by $Qd=100 - 2P$. The equilibrium price and quantity are:

Equilibrium occurs where Qd = Qs. Solving for P and Q, we get P = 25 and Q = 50. Assuming that the market supply curve is given by Qs = 2P, we can substitute Qs into the equation above:

100 - 2P = 2P

Solving for P:

100 = 4P

P = 25

Therefore, the equilibrium price is P = 25.

To find the equilibrium quantity, we substitute P = 25 into the demand curve:

Qd = 100 - 2(25) = 50

Therefore, the equilibrium quantity is Q = 50.

Hence, the equilibrium price and quantity are P = 25 and Q = 50, respectively.