25. A company manufactures and sells x pounds of beef jerky per week. Suppose the cost and revenue functions are C(x)=4000+20x,R(x)=40x100x2,0x600. (a) At a production level x=400, find the marginal cost C(400), the marginal revenue R(400), and the marginal profit P(400). (b) Use the microscope equation to approximate the changes in revenue and profit if production is increased from 400 to 410 pounds per week. (c) Suppose the company decides to expand and adds a second smoker oven. Now the cost and revenue functions are given by C(x)=5000+20x,R(x)=40x100x2,0x1200. (a) Find C(1100),R(1100), and P(1100). (b) Use the microscope equation to approximate the changes in revenue and profit if production is increased from 1100 to 1120 pounds per week. Is increasing production above 1100 a good or bad idea? (c) What is the most profitable level of production