\(3\left(x-2\right)=18\Leftrightarrow x-2=6\Leftrightarrow x=8\)
\(b,\sqrt{9.\left(x-2\right)^2}=18\)
\(\Leftrightarrow3\left|x-2\right|=18\)
\(\Leftrightarrow\left|x-2\right|=6\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=6\\x-2=-6\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-4\end{matrix}\right.\)
Vậy: \(S=\left\{8;-4\right\}\)
\(\Leftrightarrow3\left|x-2\right|=18\\ \Leftrightarrow\left|x-2\right|=6\\ \Leftrightarrow\left[{}\begin{matrix}x=6+2=8\\x=-6+2=-4\end{matrix}\right.\)
