6 doesn't even go into what you have written and when it is divided by (x - 8) you get a remainder.

The problem that is 6(x something)(x - 8) = 6( x + 9)(x -8) = 6x³ + 6x² - 432x which is not what you have written as your P(x).

2x³ + 3x² - 432x has "x" as a GCF giving: x(2x² + 3x -432) and this is as far as we can go without the Quadratic Formula.

Another possible option would be if it was 2x³ + 5x² - 432x then you get x(2x - 27)(x + 16)

Check that you copied the problem correctly.

2x^3+3x^2-432x

Factor out x:

x(2x^2+3x-432)

The trinomial is prime so that's the simplest you can get it to be.