Dalto Pizza currently sells 1000 pizzas per week at $18 per pizza. It is planning to reduce the unit price of each pizza. It estimates that for every $1 discount in price, it can sell 100 more pizzas each week.

(a) Form the weekly revenue function of Dalto Pizza in terms of p, the new unit price of the pizza.
(b) What should the new unit price be in order to maximize weekly revenue? What is the maximum weekly revenue?