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 =x + 104vx +52 Revenue: 893(x - 3)+ 28R = 18,928 dC a. Find the marginal cost at x =3. dx 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 = 3. dx The marginal revenue is estimated to be $ (Do not round until the final answer. Then round to the nearest hundredth as needed.)