Đáp án:
Giải thích các bước giải:
||x-1| - 5 | = 3
↔ \(\left[ \begin{array}{l}|x-1|-5=3\\|x-1|-5=-3\end{array} \right.\)
↔ \(\left[ \begin{array}{l}|x-1|=3+5\\|x-1|x=-3+5\end{array} \right.\)
↔ \(\left[ \begin{array}{l}|x-1|=8\\|x-1|=2\end{array} \right.\)
↔ \(\left[ \begin{array}{l}x-1=8\\x-1=-8\\x-1=2\\x-1=-2\end{array} \right.\)
↔ \(\left[ \begin{array}{l}x=8+1\\x=-8+1\\x=2+1\\x=-2+1\end{array} \right.\)
↔ \(\left[ \begin{array}{l}x=9\\x=-7\\x=3\\x=-1\end{array} \right.\)
Vậy x ∈ { -7 ; -1 ; 3 ; 9 }
