Answer:
-2
Step-by-step explanation:
The common difference of a sequence is the difference between consecutive terms. To find it, we subtract two consecutive terms.
1, -1, -3
1 and -1 are consecutive terms.
-1-1=-2
Therefore, the common difference is -2.
We can also try the same thing with -3 and -1, since they are also consecutive terms.
-3-(-1)
=-3+1
=-2
I hope this helps! Please comment if you have any questions.