Determine whether each sequence is arithmetic or geometric.Find the next three terms
1. Sequence: 3, 6, 9, 12, ...
This sequence is arithmetic with a common difference of 3.
Next three terms: 15, 18, 21
2. Sequence: 5, 10, 20, 40, ...
This sequence is geometric with a common ratio of 2.
Next three terms: 80, 160, 320