Given 6 + 2x + 3x^{3}- x^{4}, how would I rearrange it into descending order to be factored? I know addition is commutative, but given that x^{4}is negative, how do I move that without changing the expression?

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- Jan 18th 2013, 10:56 PMzsf1990Rearranging negative polynomials
Given 6 + 2x + 3x

^{3}- x^{4}, how would I rearrange it into descending order to be factored? I know addition is commutative, but given that x^{4}is negative, how do I move that without changing the expression? - Jan 19th 2013, 12:22 AMchiroRe: Rearranging negative polynomials
Hey zsf1990.

Try using:

6 + 2x + 3x^3 - x^4 = - (x^4 - 3x^3 - 2x - 6) - Jan 19th 2013, 04:07 PMzsf1990Re: Rearranging negative polynomials
Thanks! Any chance you could explain how to factor 5x

^{3}- 40? -40 isn't a perfect cube, so I'm feeling lost. This is what I get for missing a lecture I guess.

EDIT: Nevermind. Factor out a five to get x^{3}- 8, which is a difference of cubes. It's always the little things, lol. - Jan 19th 2013, 04:09 PMPlatoRe: Rearranging negative polynomials
- Jan 19th 2013, 04:10 PMzsf1990Re: Rearranging negative polynomials
I'm not sure I'm following. The question mark is a typo?

- Jan 19th 2013, 04:17 PMPlatoRe: Rearranging negative polynomials
- Jan 19th 2013, 04:25 PMzsf1990Re: Rearranging negative polynomials
Ah. My bad. It was factor 5x[sup]3 - 40.

As I move on with my homework, what are the steps to factoring this polynomial? 5(3-4x)^{2}- 8(3-4x) (5x-1) I'm not sure where to start. - Jan 19th 2013, 04:25 PMProve ItRe: Rearranging negative polynomials