Tell whether the sequence is arithmetic. If it is, what is the common difference?
-15, -9, -3, 3, ...
Responses:
A. yes;3
B. yes;5
C. yes;6
D. no
The common difference in an arithmetic sequence is the constant amount by which each term increases or decreases.
In the given sequence -15, -9, -3, 3, ... , the difference between successive terms is always 6.
Thus, the sequence is arithmetic with a common difference of 6.
Therefore, the correct response is:
C. yes;6