Determine whether each sequence is arithmetic, geometric, or neither. If the sequence is arithmetic, give a common difference; if geometric, give the common ratio.

1. 24, 19, 14, 9, 4, ...
2. 120, 60, 30, 15, ...
3. 5, 8, 13, 21, 34, ...
4. 2/27, 2/9, 2/3, 2, ...
5. 1/2, 1/4, 1/6, 1/8, ...
6. 1, 1, 2, 3, 5, 8, ...
7. 1, -5, -11, -17, ...
8. 8, 3, -2, -7, ...
9. -1/42, -1/35, -1/28, 1/21, ...
10. 4, 12, 36, 108, ...​