[tex]\bf f(x)=2|x+6|-4\implies \stackrel{f(x)}{6}=2|x+6|-4\implies 6+4=2|x+6|
\\\\\\
\cfrac{10}{2}=|x+6|\impliedby
\begin{array}{llll}
\textit{keep in mind an absolute value}\\
\textit{expression is in effect a piece-wise}
\end{array}
\\\\\\
5=|x+6|\implies
\begin{cases}
5=+(x+6)\\
5=-(x+6)
\end{cases}\implies
\begin{cases}
5=x+6\implies &-1=x\\
5=-x-6\implies &x=-11
\end{cases}[/tex]