Question

-2x + 8y + (- 21x) - 8y

Answer 1

The person above me is correct. The answer is -23x

Explanation:

you would subtract the 8y from 8y

Then add -21x to -2x to get -23x

Answer 2

-23x

Explanation:

-8y and +8y cancel, making +0.

-2x and +(-21x) simplify down to -2x -21x, and then even further down to -23x.

-23x and +0 make -23x.