For a sequence to be an arithmetic sequence the terms have to have a constant difference between them
2) We have the sequence: -12, 4, 0, 2...
The difference between the terms is not constant, so this is not a arithmetic sequence.
For example, from 4 to 0, there is -4 and from 0 to 2, is 2.
3) The sequence -6,0, 6, 12,... is an arithmetic sequence, because it has a constant difference between the terms (it always add 6 in each step).
Answer:
2. -12,4,0, 2....... No
3. -6,0, 6, 12 ..... Yes