This is a conversion problem. We know that 1 mile is 5280 feet, right? Since Ellie lives 2 miles, and two is double of 1, we just take 5280 and multiply that by two (or add it twice) to find how many feet is between Ellie's house and school. 5280 x 2 = 10560 (you get the same answer if you add 5280 twice). Therefore, 10560 feet lies between Ellie's house and school.
Add 5 to both sides to get x alone and you will have your answer which is x= -3
At 0 hours: 24 boxes
After 1 hour: 24/2 = 12 boxes
After 2 hours: 12/2 = 6 boxes
After 3 hours: 6/2 = 3 boxes
She will have 3 boxes after 3 hours.
Hope this helps :)
D= {-1}
R= {4,9,15,0}
Function? No, the relation is not a function.