economics question

1) A monopolist has the total cost function c(y) = Sy + F. The inverse demand function is p(y) = 80 - by. If the firm is losing $800 when it is required to sell the quantity demanded at a price that is equal to its marginal costs, what are its fixed costs, F? 2) Suppose a firm in a perfectly competitive environment has the following cost function: c(y) = 2yz+ F a) If profits are 200 when price is 60, what is F equal to? b) What are the firm's profits as a function of only p and F