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Homework Help: Mutiplying Rational Equations

  1. Apr 6, 2010 #1
    How do you multiply an equation that has 2 or more numerators. such as :

    8x + 8 x - 1
    ______ X _______
    X2 - 2x + 1 2x + 2




    And don't say anything like, "I'm not doing your homework for you" or anything stupid like that. I just want to know how to do it, not the answer.
     
  2. jcsd
  3. Apr 6, 2010 #2

    Doc Al

    User Avatar

    Staff: Mentor

    [tex]\frac{A}{B} \times \frac{C}{D} = \frac{A \times C}{B \times D}[/tex]

    Does that help?
     
  4. Apr 6, 2010 #3
    You must cross multiply, if I'm looking at this correctly.
    So if A/B x C/D => A x D=B x C

    So:
    8x + 8 x - 1
    ______ X _______
    X2 - 2x + 1 2x + 2
    (Yeah, I just copied that. I'm assuming that B has an x2on the bottom)

    (8x + 8)(2x+2)=(x2 - 2x)(x - 1)
    Now combine like terms, and solve for x. You will probably have to factor.
     
  5. Apr 6, 2010 #4

    Doc Al

    User Avatar

    Staff: Mentor

    You're thinking of: if A/B = C/D, then A x D = B x C

    This may or may not be what the OP meant.
     
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