Pierce Manufacturing determines that the daily revenue, in dollars, from the sale of x lawn chairs is R(x) = 0.003x + 0.01x- + 0.7x. Currently, Pierce sells 80 lawn chairs daily. a) What is the current daily revenue? b) How much would revenue increase if 84 lawn chairs were sold each day? c) What is the marginal revenue when 80 lawn chairs are sold daily? d) Use the answer from part (c) to estimate R(81), R(82), and R(83)