9, 4, -1, -7
Arithmetic because it has a common difference of 5.
4, 10, 16, 22
Arithmetic because it has a common difference of 6.
2, -6, 18, -54
Geometric because it has a common ratio of -3.
4, 4, 4, 4
Both because it has a common difference of 0 and a common ratio of 1.
Hope this helps :)