Casey and David both ride all-terrain vehicles on trails every weekend for fun. Each month, Casey rides for a total of 2x hours at an average
speed of x miles per hour. David rides 4 more hours a month than Casey, but at an average speed that is 3 miles per hour less than Casey's
average speed. Write the standard form of the function which describes the total distance, in miles, that David rides each month.

Hurry I need answer please