Question

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

19, 12.5, -2
No
Yes: 1/7
Yes; 7
Yes; -7

Answer 1

No.

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

NO.

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.