||x+3|-8|=20
=>\(\left[{}\begin{matrix}\left|x+3\right|-8=20\\\left|x+3\right|-8=-20\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}\left|x+3\right|=28\left(nhận\right)\\\left|x+3\right|=-12\left(loại\right)\end{matrix}\right.\)
=>|x+3|=28
=>\(\left[{}\begin{matrix}x+3=28\\x+3=-28\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=25\\x=-31\end{matrix}\right.\)
`#3107.101107`
`||x + 3| - 8| = 20`
\(\Rightarrow\left[{}\begin{matrix}\left|x+3\right|-8=20\\\left|x+3\right|-8=-20\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}\left|x+3\right|=28\\\left|x+3\right|=-12\left(\text{vô lý}\right)\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x+3=28\\x+3=-28\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=25\\x=-31\end{matrix}\right.\)
Vậy, `x \in {-31; 25}.`
