4. -points HARMATHAP11 12.4.007. My Notes Ask Your Tead Cost, revenue, and profit are in dollars and x is the number of units. A firm knows that its marginal cost for a product is MC - 3x + 15, that its marginal revenue is MR - 47 - 5x, and that the cost of production of 60 units is $6,480. (a) Find the optimal level of production units (b) Find the profit function. PX) (c) Find the profit or loss at the optimal level. There is a select of $ Need Help?