(8w^3+3w^2-2w-1)-(w^3+3w^2-2w)?

Question

My answer is 7w^3-1.

What does everyone else get?

Answer 1

my answer is 11w

Answer 2

I believe that your answer is correct but lets go through the motions to indeed verify that it is the case:

(8w^3+3w^2-2w-1)-(w^3+3w^2-2w)
= (8w^3 - w^3) + (3w^2 - (+3w^2)) + (-2w - (-2w)) - 1
= (8 - 1)w^3 + (3w^2 - 3w^2) + (-2w + 2w) - 1
= 7w^3 + 0 + 0 - 1
= 7w^3 - 1

So, why did you doubt yourself?

Answer 3

The 7w^3-1 answer seems to be correct