Question

11. Tell whether the sequence is arithmetic. If it is, what is the common difference?

Answer 1

Answer:

No.

Step-by-step explanation:

19 - 12.5 = 6.5

12.5 - (-2) = 14.5

The differences between two pairs of consecutive numbers of the sequence are not equal, so there is no common difference, and the sequence is not arithmetic.

Answer 2

Answer:

NO.

Step-by-step explanation:

The given sequence is

$19,12.5,-2$

The given sequence is not arithmetic, because there's no difference pattern. For example, the difference between 12.5 and 19 is -6.5, and the difference between 12.5 and -2 is 14.5, therefore it's not an arithmetic sequence, because they difference is not the same for all terms.

Therefore, the answer is the first choice NO.