Suppose that we're making and selling some widget and the revenue (in dollars) when making a widgets is R(z) =9(12x+1)0.25-9. What are the average revenue and marginal average revenue functions, and what is the marginal average revenue at a given production level? The average revenue function is R(z) = The marginal average revenue function is R' (z) = If we're already making 61 widgets, by how much will our average revenue per widget change if we increase production by one unit? $ decimal places if rounding is needed) (round to 4