Hãy tìm x, biết: \(\sqrt {{{\left( {2{\rm{x}} - 1} \right)}^2}}  = 3\)

* Hướng dẫn giải

\( \sqrt {{{\left( {2{\rm{x}} - 1} \right)}^2}} = 3 \)
\( \Leftrightarrow \left| {2{\rm{x}} - 1} \right| = 3 \)

\(\begin{array}{l}
\Leftrightarrow \left[ \begin{array}{l}
2x - 1 = 3\\
2x - 1 = - 3
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
2x = 4\\
2x = - 2
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x = 2\\
x = - 1
\end{array} \right.
\end{array}\)

Vậy \(x=-1;x=2.\)