arithmetic and geometric sequences

Find the eighth term: 3, 6, 12, 24, ...

Which sequence is a geometric sequence with a common ratio of 2? 5, 3, 1, -1, ..., 5, 7, 9, 11, ..., 5, 10, 20, 40, ..., 5, 15, 45, 135, ...

What are the next 3 terms in this sequence of terms? 3, 7, 11, 15

Which kind of sequence has a common difference? Options: Arithmetic, Geometric

Which of the following best describes this sequence? $$\left\{135,\ 45,\ 15,\ 5,\ ...\right\}$$

Arithmetic, geometric, or neither? 1, 3, 7, 13, ...

Find the next term: 81, 9, 1, 1/9, ...

What kind of sequence is illustrated below?
 400, 200, 100, 50, 25, ...

Find the common difference: 25, 13, 1, -11, ...

What is the common ratio of the geometric sequence below?
5, 25, 125, 625...