1. A firm is the only producer of a particular good. The firm's marginal revenue function is MR = 9 - q, where q denotes the quantity of the good produced by the firm. The firm's fixed costs are 12 and its average variable cost function is 1 + q/2. Find an expression for the firm's profit function, ̠(q). Find the value of the production, q, which maximises the firm's profit, and hence calculate the firm's maximum profit.