Respuesta :

Answer:

Step-by-step explanation:

In an arithmetic sequence, the consecutive terms differ by a common difference, d. Therefore,

d = Term 2 - Term 1 = Term 3 - Term 2

In an geometric sequence, the consecutive terms differ by a common difference, r. Therefore,

r = Term 2 /Term 1 = Term 3 / Term 2

1) 128, 32, 8, 2, .. Is a geometric sequence

r = 32/128 = 1/4

2) 1, 3, 9, 27, .. Is a geometric sequence

r = 3/1 = 3

3) 5, 10, 15, 20, ...is an arithmetic sequence

d = 10 - 5 = 5

4) 20, 17, 14, 11, … is an arithmetic sequence

d = 17 - 20 = - 3