Please solve this: a resident in a particular city pays a water bill of $3.66 per month plus $2.43 per 1000 gallons of water (used up to 4000 gallons). If the city has 677,000 costumers that use less than 4,000 gallons per month. Find it's monthly revenue function R(x). Where total number of gallons x measured in thousands. R(x)=