The dally marginal revenue function associated with selling x widgets is given by R (x) - -18x2 + 10x + 45 where R'(x) is measured In dollars per unit per day and x denotes the number of widgets produced and sold. (a) Determine the revenue function, R(x), associated with producing and selling x widgets. R(X) = (b) Determine the demand function relating unit price, p(x), to the quantity demanded, x. p(x) =