Identify each sequence as arithmetic,geometric,or neither

Question

1. -1,3,-9,27
2. 1,2,4,7,11
3. 5,3,1,-1,-3
4. 6,3,3/2,3/4

Answer 1

1. each new term is the result of multiplying the previous term by -3
which makes it geometric, since we have a common ratio of -3
2. I see neither a common ratio, nor a common difference.
3. looks like we have a common difference of -2
4. looks like a term was multiplied by 1/2 to get to the next term, so ....