What is the factored version of 8-r^3

To factor a cube (a^3-b^3) = (a-b)(a^2+ab+b^2)

8 is the cube of 2
r^3 is the cube of r.

So, a is 2 and b is r

(2-r)(2^2+2r+r^2)

(2-r)(4+2r+r^2)

The answer to your question is (2-r)(4+2r+r^2)

Ithink it would be 160 people