Algebra-1

To find which sequence is not an arithmetic sequence, check if the differences between consecutive terms are consistent.

For 3, 6, 9, 12, 155:

Differences: 6 − 3 = 3, 9 − 6 = 3, 12 − 9 = 3, 15 − 12 = 3

Differences are consistent (3), so this is an arithmetic sequence.

For 10, 20, 30, 40, 50:

Differences: 20 − 10 = 10, 30 − 20 = 10, 40 − 30 = 10, 50 − 40 = 10

Differences are consistent (10), so this is an arithmet...