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Math Help - I can't see how they solve this equation!

  1. #1
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    I can't see how they solve this equation!

    This is one line in an optimization problem…

    x2[3600+(200-x)2 ] = (200-x)2(8100+x2)

    According to the book it should equal…

    3600x2 = 8100(200-x)2

    I can’t see how!
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  2. #2
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    Quote Originally Posted by NFZ17 View Post
    This is one line in an optimization problem…

    x2[3600+(200-x)2 ] = (200-x)2(8100+x2)

    According to the book it should equal…

    3600x2 = 8100(200-x)2

    I can’t see how!
    Is it
    x^2[3600+(200-x)^2]=(200-x)^2(8100+x^2)
    ??
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  3. #3
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    Yeah that's it, sorry I copied and pasted from a word doc!!
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  4. #4
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    Quote Originally Posted by NFZ17 View Post
    This is one line in an optimization problem…

    x2[3600+(200-x)2 ] = (200-x)2(8100+x2)

    According to the book it should equal…

    3600x2 = 8100(200-x)2

    I can’t see how!
    x^2[3600+(200-x)^2]=(200-x)^2(8100+x^2)

    Multiplying these out, we get...

    3600x^2+x^2(200-x)^2=8100(200-x)^2+x^2(200-x)^2

    therefore, since x^2(200-x)^2 is common to both sides..

    3600x^2=8100(200-x)^2
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  5. #5
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    Thanks a million! totally missed that!
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