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Math Help - Factoring a sum or difference of cube

  1. #1
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    Factoring a sum or difference of cube

    How do you factor this cube:

    (x+5)^3 - (2x+1)^3
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  2. #2
    Super Member Quacky's Avatar
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    Quote Originally Posted by Devi09 View Post
    How do you factor this cube:

    (x+5)^3 - (2x+1)^3
    (a^3-b^3)=(a-b)(a^2+ab+b^2)

    Let a=x+5 and b=2x+1.

    It isn't pretty!
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  3. #3
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    e^(i*pi)'s Avatar
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    As these are cubics you may want to consider expanding using the binomial theorem and collecting like terms.

    Unless, of course, you've been instructed to use the difference of two cubes
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