$\left[\begin{matrix} x=x+2\\ x=-(x+2)\end{matrix}\right.$
$\left[\begin{matrix} x-x=2\\ x=-x-2\end{matrix}\right.$
$\left[\begin{matrix} 0=2 (Vô-lí)\\ x+x=-2\end{matrix}\right.$
$\left[\begin{matrix} 0=2 (Vô-lí)\\ 2x=-2\end{matrix}\right.$
$\left[\begin{matrix} 0=2 (Vô-lí)\\ x=-2:2\end{matrix}\right.$
$\left[\begin{matrix} 0=2 (Vô-lí)\\ x=-1(Chọn)\end{matrix}\right.$
$\text{Vậy}$ `x = -1`
