Suppose that the revenue realized on the sale of company's product can be modeled by the function R(x) = 500x -0.4x is the number of

Suppose that the revenue realized on the sale of company's product can be modeled by the function R(x) = 500x -0.4x² is the number of units sold and R(x) is given in dollars. (Revenue is the income a company receives from selling its goods at services. Compute the average change in revenue, per additional item that was sold for the first 50 items.