Please help me with math

Answer:
1.) Arithmetic. common difference: 4
2.) Arithmetic. common difference: 4
3.) Not arithmetic.
Answer:
Step-by-step explanation:
The first two have a common difference of 4
2 6 10
To get from 2 to 6 you need to add 4 to the 2.
-7 -3 1
Add 4 to -3 and you get 1. This works.
The last one seems to be playing hop scotch all over the place (hop scotch is not a technical term. It is just by way of saying it's not arithmetic).