Marginal Cost The cost C (in dollars) of producing X units of a product is given by the following. C = 2.8V"; + 400 (a) Find the marginal cost (in dollars per unit) when X = 9. (Round your answer to two decimal places.) (b) Find the additional cost (in dollars) when the production increases from 9 to 10 units. (Round your answer to two decimal places.) $|:l (c) Compare the results of parts (a) and (b)