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    :confused: could anyone show me how to solve this:
    the mod of (3x+5)= the mod of 5x
    the answer is in the back of the book and there's 2 solutions but I dont know how to get the 2nd one.
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    What you have to do is square both sides, you will get a quadratic to solve.

    |3x+5|= |5x|

    9x^2 + 30x + 25 = 25X^2

    16x^2 - 30x -25 = 0

    (2x - 5)(8x + 5) = 0

    so x = 5/2 and -5/8
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    Alternative solution
    |3x+5| = |5x|

    or,

    (3x+5) = ± 5x
    ===========

    1st soln
    3x + 5 = 5x
    5 = 2x
    x = 5/2
    ======

    2nd soln
    3x + 5 = -5x
    5 = -8x
    x = -5/8
    ======

    It would be simpler doing it this way if you had something like,

    |2x² + 3x + 5| = |x² + 5x + 1|
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    thanks alot you guys.
 
 
 
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Updated: August 5, 2004

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