7. DETAILS HARMATHAP12 9.5.003. Find the derivative and simplify. dy dx y = (4x+3)(9x6 - 5x4 - 6) 8. DETAILS HARMATHAP12 9.9.020.MI. If the cost function for a commodity is 1 C(x) x3 + 6x2 + 6x + 16 dollars 90 find the marginal cost MC at x = 9 units. (Round your answer to two decimal places.) MC = $ Tell what the marginal cost predicts about the cost of producing 1 additional unit. The cost of producing 1 additional unit is $ Tell what the marginal cost predicts about the cost of producing 2 additional units. The cost of producing 2 additional units is $