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1. 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.
2. 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
3. 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|
4. thanks alot you guys.

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Updated: August 5, 2004
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