Consider a firm in a perfectly competitive market with total costs given by TC = Q3 – 15Q2 + 100Q + 30 a.) What is this firm’s marginal cost function? Over what range of output are the firm’s marginal costs decreasing? Increasing? b.) Suppose that the market price is $52. What is this firm’s profit-maximizing level of output? How do you know this is the profit-maximizing output? How much profit does this firm earn by producing the profit-maximizing output?