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Math Help - Factor out COMPLETELY

  1. #1
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    Factor out COMPLETELY

    Please provide steps to factoring out this expression:

    x^3 y^2 - 9x^3 - 8y^2 + 72

    Thanks much!
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  2. #2
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    Quote Originally Posted by chopstixdcb View Post
    Please provide steps to factoring out this expression:

    x^3 y^2 - 9x^3 - 8y^2 + 72

    Thanks much!
    x^3 (y^2-9)-8 (y^2-9)=0

    (y^2-9)(x^3-8)=0

    Then here, make use of the identities:

    a^2-b^2=(a+b)(a-b)

    <br />
a^3-b^3=(a-b)(a^2+ab+b^2)
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  3. #3
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    So is this right?

    (x-2)(x^2+2X+4)(y+3)(y-3)(y+3)(y-3)?
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  4. #4
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    Quote Originally Posted by chopstixdcb View Post
    So is this right?

    (x-2)(x^2+2X+4)(y+3)(y-3)(y+3)(y-3)?
    Why did you give an extra of 2 factors? The last 2?
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  5. #5
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    I forgot, I understand now. The (y^2-9) allows me to group the (x^3-8). So I don't need those last two factors. Thanks so MUCH!
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