Answer:
Explanations:
Note that for a sequence to be arithmetic, there must be a common difference, d.
Considering each of the sequences provided:
For -1, 3, -9, 27, -81.........
3 - (-1) = 4
-9 - 3 = -12
27 - (-9) = 36
Since the differences between consecutive terms are not common, this is not an arithmetic sequence.
For 1, -2, -5, -8, -11....
-2-1 = -3
-5 -(-2) = -3
-8 - (-5) = -3
-11 - (-8) = -3
Since there is a common difference, d = -3, the sequence is an arithmetic sequence
For 26, 39, 52, 65, 78.....
39 - 26 = 13
52 - 39 = 13
65 - 52 = 13
78 - 65 = 13
Since there is a common difference of