Question

Which answer describes the type of sequence?

3, 9, 15, 21, ...

1.neither arithmetic nor geometric
2.arithmetic
3.geometric

Answer 1

2. arithmetic.

Explanation:

This is arithmetic because successive terms increase by 6.

Answer 2

2. arithmetic

Explanation:

Differences between adjacent terms are all 6, so the sequence is arithmetic.

_____

An arithmetic sequence has terms with a common difference.

A geometric sequence has terms with a common ratio.