A firm in a perfectly competitive 'industry has this cost function: TC = 900 + q^2

a) If market demand is QD = 1800 - 20P, what is the long-run equilibrium price, quantity produced by the firm and the industry, and the number of firms in the industry?

b)  If demand increases by 600 for all Q, what is the short-run price, quantity, and profit for the firm and the industry? In the long-run how many firms enter the industry?

c) If each firm has to pay a one-time licensing fee, in the short-run what happens to the market price and quantity, and each firm's output and profits? What happens to the number of firms in the long-run? (No calculations necessary.)