For a certain product, cost C and revenue R are given as follows, where x is the number of units sold in hundreds. Cost: C- =x = x2 + 108 x +50 Revenue: 892(x - 6)~ + 28R- =23,548 dC a. Find the marginal cost at x = 6. 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 = 6. dx The marginal revenue is estimated to be $ (Do not round until the final answer. Then round to the nearest hundredth as needed.)