The answer is (9a3-10) (9a3+10)
Lets say that the day they both take off is day 0.
The next day Sandy takes off will be day 4, and Morgans will be day 10.
Sandy will take off 4, 8, 12, 16, and 20.
Morgan will take off 10, 20, 30, 40, and 50.
Both Morgan and Sandy take off day 20, so the next time they have a day off together will be in 20 days.
Answer: X - 10 = How many books Carla has
Step-by-step explanation: Carla has 10 FEWER books than Dominic and we will represent Dominic with X we don't know what X is and no matter what the number is Carla always has 10 less so X(Dominic's books) - 10(How many fewer books) = How many books Carla has.
