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Topic: Factoring
Replies: 52   Last Post: Jan 16, 2012 8:23 PM

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Marnie Northington

Posts: 665
Registered: 12/13/04
Factoring
Posted: Jan 8, 2012 8:35 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

A student asked me how to factor x^3-3x^2-4x+12
So I took a guess (correctly it seems) that since 12 factors as 2,2,3 one of
the factors was likely to be x-2. Dividing by x-2 gives x^2-x-6 which is
easy to factor into (x-3)(x+2) so the answer is (x-2)(x-3)(x+2).

Is there a way to do that whithout guesswork?

Suppose I had a more complicated example such as (2x+1)(3x-2)(4x+5) I
haven't multiplied it out but how would I find the factors if I didn't know
them in advance?

Thanks for any enlightenment.

old guy




Date Subject Author
1/8/12
Read Factoring
Marnie Northington
1/8/12
Read Re: Factoring
LudovicoVan
1/8/12
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Marnie Northington
1/8/12
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Peter Webb
1/8/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Peter Webb
1/9/12
Read Re: Factoring
Pubkeybreaker
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Peter Webb
1/10/12
Read Re: Factoring
Pubkeybreaker
1/10/12
Read Re: Factoring
Peter Webb
1/9/12
Read Re: Factoring
Bart Goddard
1/9/12
Read Re: Factoring
Virgil
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Pubkeybreaker
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Pubkeybreaker
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
William Hale
1/9/12
Read Re: Factoring
Shmuel (Seymour J.) Metz
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Virgil
1/9/12
Read Re: Factoring
Marnie Northington
1/9/12
Read Re: Factoring
Peter Webb
1/9/12
Read Re: Factoring
Marnie Northington
1/10/12
Read Re: Factoring
Shmuel (Seymour J.) Metz
1/10/12
Read Re: Factoring
Pubkeybreaker
1/10/12
Read Re: Factoring
Marnie Northington
1/11/12
Read Re: Factoring
Pubkeybreaker
1/11/12
Read Re: Factoring
Marnie Northington
1/11/12
Read Re: Factoring
Pubkeybreaker
1/11/12
Read Re: Factoring
Marnie Northington
1/11/12
Read Re: Factoring
Pubkeybreaker
1/11/12
Read Re: Factoring
Dave L. Renfro
1/11/12
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Pubkeybreaker
1/11/12
Read Re: Factoring
Marnie Northington
1/11/12
Read Re: Factoring
Marnie Northington
1/11/12
Read Re: Factoring
Dave L. Renfro
1/11/12
Read Re: Factoring
Marnie Northington
1/11/12
Read Re: Factoring
Dave L. Renfro
1/11/12
Read Re: Factoring
Marnie Northington
1/12/12
Read Re: Factoring
Dave L. Renfro
1/12/12
Read Re: Factoring
Marnie Northington
1/12/12
Read Re: Factoring
Dave L. Renfro
1/12/12
Read Re: Factoring
Marnie Northington
1/13/12
Read Re: Factoring
Dave L. Renfro
1/12/12
Read Re: Factoring
Frederick Williams
1/12/12
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Marnie Northington
1/12/12
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Robert H. Lewis
1/12/12
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Marnie Northington
1/12/12
Read Re: Factoring
r3769@aol.com
1/16/12
Read Re: Factoring
amzoti

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