The sequence is Arithmetic and the common difference is 2
The form of a arithmetic sequence is

we know the first term of the sequence: -36. Doing the calculations for a2:

The difference between the first and second term is 2. If this is a arithmetic sequence, d has to be the same for all other terms of the sequence.
let's see:
-34+2=-32
-32+2=-30
Thus, the sequence is arithmetic and d=2