Assignment: add and subtract rational expressions choose any four (4) of the following five problems to solve. show all work leading to your answer. 1. randy drives his car to work each day. suppose the expression 66 3 xx represents the total time it takes randy to drive to work in a day, where x represents the average speed of the car in miles per hour, during the first part of the drive. a. use addition to simplify the expression 66 3 xx . show all the steps necessary to write the expression with a common denominator and to simplify the expression. b. if the speed of the car was 24 mph during the first part of the drive, find the total amount of time it took randy to drive to work that day.