This is difference between two cubes:
Can you do it now?
. . . . This is not factored!
For example -- Factor: .
"Factor" means to express it as a product of two or more expressins.
. . Answer: .
This is not factored: .
Certainly, parts of it are factored, but it is still a sum of two expressions.
We have: . . . . difference of cubes!
. . You are expected to know that: .