Answer:
It is an arithmetic sequence
Common difference is -4
Step-by-step explanation:
Here, we want to determine the type of sequence
As we can see, the difference between each of the terms is as follows;
13-17 = 9-13 = -4
What this mean is that we have a constant common difference
This simply shows that the sequence we have is an arithmetic sequence
The common difference is thus;
13-17 = 9-13 = -4
