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#1 2012-11-28 21:07:15

deiv
Guest

factoring polynomials

Pls factor completely: (m^9)-(3m^3)-2
tnx....

#2 2012-11-28 22:41:01

bob bundy
Moderator

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Re: factoring polynomials

hi deiv

Welcome to the forum.



You can simplify the problem by making the substitution



Then it becomes



I notice that x = -1 makes this expression zero, so by the factor theorem (x + 1) is a factor.

From there you can easily get the quadratic that goes with this and you'll find the formula will give another two factors.

Then you can go back to the m expression from there.

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

#3 2012-11-28 23:19:05

bobbym
Administrator

Online

Re: factoring polynomials

Hi;

Or take it over to Wolfram.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

#4 2012-11-28 23:34:45

deiv
Guest

Re: factoring polynomials

How about this one? What are the factors of:
3x(x+2y) + 4y(3x+2y)

#5 2012-11-28 23:55:10

bob bundy
Moderator

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Re: factoring polynomials

What do you get if you multiply out the brackets and simplfy?

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

#6 2012-11-29 00:30:59

bobbym
Administrator

Online

Re: factoring polynomials

I think you are going to find that is irreducible in Q and therefore in Z.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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