Find the common difference of the arithmetic sequence 1,-1, -3, ...

-2

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.