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[Core 4] Rational Fractions

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    Here is the question:
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    I did
    A(x+1)(x+5) + B(x-1)(x+5) + C(x-1)(x+1) = 3x2 + 28x + 17

    Then to work out each constant:

    A: let x = 1
    12A = 3 + 28 + 17 => A = 4

    B: let x = -1
    -8B = 3 - 28 + 17 => B = 4

    C: let x = -5
    24C = 192 - 140 + 17 => C = 2.875

    However when I add my three fractional components on WolframAlpha, I do not get the same answer as I what I am trying to express.

    Help would be appreciated, thanks.
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    Mistake on B and C,

    -8B = 3-28+17

    -8B = -8

    so B=....

    and For C, 3(-5)^2 = 75 not 192
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    (Original post by NotNotBatman)
    Mistake on B and C,

    -8B = 3-28+17

    -8B = -8

    so B=....

    and For C, 3(-5)^2 = 75 not 192
    Damn.. My mistakes were so stupid. I got B = 1 and C = - 2, is this correct?
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    (Original post by DarkEnergy)
    Damn.. My mistakes were so stupid. I got B = 1 and C = - 2, is this correct?
    Yes, that's correct.
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    (Original post by NotNotBatman)
    Yes, that's correct.
    Thanks for your help!
 
 
 
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