Can You Solve This Absolute Value Inequality Proof?

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    Inequality Proof
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Homework Statement



l lxl - lyl l =< lx-yl

Homework Equations



n/a

The Attempt at a Solution



how do i proof this? give me a start please, should i use definition absolute values and consider all of the cases? or use triangle inequality(but i can't figure out how)
 
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hey i get it, use x=(x-y)+y
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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