Thinking Mathematically (6th Edition)

A sequence is: (a) arithmetic if there is a common difference among the terms; or (b) geometric if there is a common ratio among the terms. Notice that the given sequence has terms that increase by 4. This means that the sequence has a common difference of 4. Thus, the sequence is $\underline{\text{arithmetic}}$. The next two terms can be found by adding 4 to the previous term. Therefore, the next two terms are: $3+4=7 \\7+4=11$