F. determine whether each sequence is arithmetic or not. find the common difference for each arithmetic sequence 1. 4, 8, 12, 16,.. 2. 13, 10, 7, 4,... 3. -10, -8, -6, -4,.. 4. 1, 6, 8, 11, 12,.. 5. 5, 6, 12, 13