A total-revenue function is given below where R(x) is the total revenue. in thousands of dollars. from the sale of :r: items. Find the rate at which total revenue is changing when 30 items have been sold. * Rm = moot/9m? + a: .I. Add file A total-cost function is given below where C(x) is the total cost. in thousands of dollars. of producing 3: items. Find the rate at which total cost is changing when 15 items have been produced. * C(33) = 130(3;2 + a)\"3 + 100