\(\left|x+9\right|.2=10\)
\(\Rightarrow\left|x+9\right|=10:2\)
\(\Rightarrow\left|x+9\right|=5\)
\(\Rightarrow\left[\begin{matrix}x+9=5\\x+9=-5\end{matrix}\right.\)
\(\Rightarrow\left[\begin{matrix}x=5-9\\x=\left(-5\right)-9\end{matrix}\right.\)
\(\Rightarrow\left[\begin{matrix}x=-4\\x=-14\end{matrix}\right.\)
Vậy \(\left[\begin{matrix}x=-4\\x=-14\end{matrix}\right.\)
