Algebra-1

To identify the arithmetic sequence, check if the difference between consecutive terms is constant:

For 101, 205, 329, 413, 517:

Difference between 205 and 101: 205 − 101 = 104

Difference between 329 and 205: 329 − 205 = 124

Difference between 413 and 329: 413 − 329 = 84

Difference between 517 and 413: 517 − 413 = 104

The differences are not constant, so this is not an arithmetic sequence.

For 123, 246, 369, 492, 615:

Difference between 246 and 123: 246 − 123 = 123

Difference between 369 and 246: 369 − 246 = 123

Difference between 492 and 369: 492 − 369 = 123

Difference between 615 and 492: 615 − 492 = 123

The common difference is consistently 123, so this is an arithmetic sequence.