Work these problem. (See Example.)For the year 2013, a resident of the city of Dallas, Tex...

Work these problem. (See Example.)

For the year 2013, a resident of the city of Dallas, Texas with a 5/8 inch water meter pays $4.20 per month plus $1.77 per 1000 gallons of water used (up to 4000 gallons). If the city of Dallas has 550,000 customers that use less than 4000 gallons a month, find its monthly revenue function R (x), where the total number of gallons x is measured in thousands.

Example

The energy company New York State Electric and Gas charges each residential customer a basic fee for electricity of $15.11, plus $.0333 per kilowatt hour (kWh).