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 noname November 14th, 2006 06:30 PM

factor polynomial

i just need some help with factoring

12x^7z^2 - 18x^4z^4 - 24x^5z^6
i got to this point but dont know where to go from here
6x^4z^2(2x^3 - 3z^2 - 4xz^4)

and then i have another problem that i have no idea where to start
8x^3 - y^9

Thanks

 julien November 14th, 2006 07:39 PM

Re: factor polynomial

Quote:
 Originally Posted by noname i just need some help with factoring 12x^7z^2 - 18x^4z^4 - 24x^5z^6 i got to this point but dont know where to go from here 6x^4z^2(2x^3 - 3z^2 - 4xz^4)
Well, nothing says that you can factor further. In fact, if you are trying to factor in R[x,z], then maybe 2x^3-3z^2-4xz^4 is irreducible there. If such is the case, then maybe you should try to prove it (PS: i haven't tried so maybe there is a factorization).

Quote:
 Originally Posted by noname and then i have another problem that i have no idea where to start 8x^3 - y^9 Thanks
For this one this is easy: use a^3-b^3=(a-b)(a^2+ab+b^2)

 noname November 17th, 2006 07:39 AM

thx

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