this sequence is decreased by 3 for every digit
so
-3n+18
Answer
The cheaper dog sitter is Derrick's.
Step-by-step explanation:
You did not really ask a question here but i am assuming that your asking who is the cheaper route.
Answer:
9
6 divided by 2 = 3
1 +2 = 3
3 x 3 = 9
-13/5