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Math Help - Old guy helping daughter

  1. #1
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    Old guy helping daughter

    We have no book and I am trying to go through example problems. I probably need to get a book and learn this all over again. 50 years old no and not done this since 20 years old.

    2xsquared-8x+2=0

    (2x-2)(1x-1) gets me 4x in the middle when I multiply it through.

    Is this the right way to approach this, did I do something silly?
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  2. #2
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    Quote Originally Posted by jonb View Post
    We have no book and I am trying to go through example problems. I probably need to get a book and learn this all over again. 50 years old no and not done this since 20 years old.

    2xsquared-8x+2=0

    (2x-2)(1x-1) gets me 4x in the middle when I multiply it through.

    Is this the right way to approach this, did I do something silly?
    Since your factoring. I would think that you would factor a 2 out of the whole problem. I don't know what would go into 1 and add up to -4 though. So my post is basically useless.

    Factor out a 2(x^2-4x+1)
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  3. #3
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    Quote Originally Posted by Matrim View Post
    Since your factoring. I would think that you would factor a 2 out of the whole problem. I don't know what would go into 1 and add up to -4 though. So my post is basically useless.

    Factor out a 2(x^2-4x+1)
    That's because nothing does. You can tell if a quadratic has integer factors by looking at the discriminant, \Delta

    [tex]\Delta = b^2-4ac = 16-(4)(1)(1) = 12[/MATh]. As 12 is not a square number this does not have integer factors and your factorisation is as far as it goes although the 2 can be cancelled
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  4. #4
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    Got it.

    Can anyone recommend a book to relearn all of this?

    Thanks
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  5. #5
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    Quote Originally Posted by jonb View Post
    Got it.

    Can anyone recommend a book to relearn all of this?

    Thanks
    Perhaps Amazon.com: Engineering Mathematics (9780831133276): K. A. Stroud, Dexter J. Booth: Books
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