The factors of this polynomial would be (x + 4)(x + 2)(x - 1).
To find these, you first have to start with long division to find the first factor. If you use x + 4 it would look like this.
=
Now we are left with only . We can factor this by looking for numbers that multiply to the last number and add to the middle number. 2 and -2 multiply to -2 and add to 1. Therefore, we'll use those in parenthesis in their place.
(x + 4)(x + 2)(x - 1)