|x-3|-7=13
=> |x-3|=20
=> \(\left[{}\begin{matrix}x-3=20\\x-3=-20\end{matrix}\right.=>\left[{}\begin{matrix}x=23\\x=-17\end{matrix}\right.\)
\(\left|x-3\right|-7=13\\ \left|x-3\right|=13+7\\ \left|x-3\right|=20\)
\(\circledast\)TH1: x-3=20
x=20+3
x=23
\(\circledast\)x-3=-20
x=-20+3
x=-17
Vậy \(x\in\left\{-17;23\right\}\).
\(|x-3|-7=13\)
\(|x-3|=20\)
\(\Rightarrow x-3=20\) hoặc \(x-3=-20\)
\(\Rightarrow x=23\) hoặc \(x=-23\)
Vậy \(x\in\left\{23;-23\right\}\)