QUIZ: Quiz Week y (LEV, LET] For a certain product, cost C and revenue R are given as follows, where x is the number of units sold in hundreds. Cost: C2 =x2 + 110Vx +57 Revenue: 895(x - 4)2+ 30R = 18,750 dc a. Find the marginal cost - at x = 4. The marginal cost is estimated to be $ (Do not round until the final answer. Then round to the nearest hundredth as needed.) dR b. Find the marginal revenue at x = 4. dx The marginal revenue is estimated to be $ (Do not round until the final answer. Then round to the nearest hundredth as needed.)