bearing in mind that an absolute value expression is in effect a piece-wise function with two cases, thus
[tex]\bf |-n|=
\begin{cases}
+(-n)\\
-(-n)
\end{cases}\implies
\begin{cases}
-n\\
n
\end{cases}
\\\\\\
n|-n|=2n\implies
\begin{cases}
n-n=2n\implies 0=2n\implies &0=n\\
n+n=2n\implies 2n=2n\impliedby &inconsistent
\end{cases}[/tex]
