# How do i factor this polynomial?

• Feb 20th 2013, 10:08 PM
kaboose786
How do i factor this polynomial?
Hey i would appreciate if someone can guide me on how to factor this:

x^3 + 4x^2 - 2x + 3

I know the answer should be -4.5797, and 0.2899 +- 0.7557i
• Feb 22nd 2013, 02:35 AM
kaboose786
Re: How do i factor this polynomial?
• Feb 22nd 2013, 03:28 AM
MINOANMAN
Re: How do i factor this polynomial?
if p,q,r are the roots then p(x)=(x-p)(x-q)(x-r)
use this formula to factorise your polynomial since you know already the roots.
• Feb 22nd 2013, 03:40 AM
kaboose786
Re: How do i factor this polynomial?
Quote:

Originally Posted by MINOANMAN
if p,q,r are the roots then p(x)=(x-p)(x-q)(x-r)
use this formula to factorise your polynomial since you know already the roots.

well i got those roots from a computional program called Matlab. Is it possible to solve this by hand?
• Feb 22nd 2013, 06:07 AM
HallsofIvy
Re: How do i factor this polynomial?
What do you mean by "factoring" here? Normally, we mean "factoring with integer coefficents". Since none of the zeros of this polynomial are integer, that is clearly impossible.
• Feb 22nd 2013, 06:36 AM
MINOANMAN
Re: How do i factor this polynomial?
Any polynomial nth degree can be factorized regardless the nature of its roots...following the well known theorem of algebra.
Kaboose 786 the equation you gave us is a cubic and cannot be solved easily.
you may use a C.A.S to get the roots..There is nothing wrong using math lab or maple...it will help you.
There are some simple qalculators that can be programmed to solve qubic equations as well.
Try them
Good luck
MINOAS
• Feb 22nd 2013, 06:55 AM
Prove It
Re: How do i factor this polynomial?