Consider the cost function C(x)=5x^(2)+14 x+23 (thousand dollars). a) What is the marginal cost at production level x=6 ? b) Use the marginal cost at x=6 to estimate the cost of producing 6.25 units. c) Let R(x)=-x^(2)+27 x+38 denote the revenue in thousands of dollars generated from the production of x units. What is the break-even point? (Recall that the break-even point is when the revenue is equal to the cost.) d) Compute and compare the marginal revenue and marginal cost at the break-even point. Should the company increase production beyond the break-even point