May I please get some help

9 An accessories company nds that the revenue, in dollars, from the sale of x belts is given by R(x) = 45x 10 . Find the rate at which average revenue is changing when 171 belts have been produced and sold. 0 First, nd the rate at which the average revenue is changing when x belts have been produced. '(x) = D 1 When 171 belts have been produced and sold. the average revenue is changing at [:I for each additional belt. (Round to four decimal places as needed.)