(2x-1)-3√(2x-1)=0

$\displaystyle  \begin{array}{{>{\displaystyle}l}}
\ \ \ \ \ \ ( 2x-1) -3\sqrt{2x-1} =0\ \ \ \left( x\geqslant \frac{1}{2}\right)\\
\Leftrightarrow \sqrt{2x-1} .\left(\sqrt{2x-1} -3\right) =0\\
\Leftrightarrow \left[ \begin{array}{l l}
\sqrt{2x-1} =0 & \\
\sqrt{2x-1} -3=0 & 
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l l}
2x-1=0 & \\
2x-1=9 & 
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l l}
2x=1 & \\
2x=10 & 
\end{array} \right.
\end{array}$
$\displaystyle \Leftrightarrow \left[ \begin{array}{l l}
x=\frac{1}{2} & \\
x=5 & 
\end{array} \right.$ (đều thỏa mãn $\displaystyle x\geqslant \frac{1}{2}$)