Since the difference is the same for each set, you can say that the common difference is 3. Therefore, you can say that the formula to find the common difference of an arithmetic sequence is: d = a(n) - a(n - 1), where a(n) is the last term in the sequence, and a(n - 1) is the previous term in the sequence.
Step-by-step explanation:
The common difference is the distance between each number in the sequence. Notice that each number is 3 away from the previous number. Thus, the common difference is 3.
