Suppose the demand​ d, in units​ sold, for a​ company's jeans at price​ x, in​ dollars, is d(x)=800−4x.

A. If revenue=price×demand​, write the rule for the function​ r(x), which represents the​ company's expected revenue in jean sales. Then state the domain of this function.

B. If the price is ​$30​, how much revenue will the company​ earn?

A. The rule for the function​ r(x) is ​r(x)=