The domain of the function is the values r can take. Here it's the number of subway rides. Since Clair only can pay for a whole number of rides, the domain is 0,1,2,3… However, there is a highest value r can take since she can't have a negative balance, b, on her card. Let's find the function's domain.
| r
|
17−2.75r
|
b
|
| 0
|
17−2.75⋅0
|
17
|
| 1
|
17−2.75⋅1
|
14.25
|
| 2
|
17−2.75⋅2
|
11.5
|
| 3
|
17−2.75⋅3
|
8.75
|
| 4
|
17−2.75⋅4
|
6
|
| 5
|
17−2.75⋅5
|
3.25
|
| 6
|
17−2.75⋅6
|
0.5
|
| 7
|
17−2.75⋅7
|
-2.25
|
Clair can only pay for 6 subway rides with the money she has on her OMNY card as 7 rides would make the balance on the card negative. D: {0,1,2,3,4,5,6}
