~ Bạn tham khảo ~
`x(2x-1)=2x`
`<=> 2x^2-x=2x`
`<=> 2x^2 - x - 2x = 0`
`<=> 2x^2-3x = 0`
`<=> x(2x-3)=0`
\(⇔\left[ \begin{array}{l}x=0\\2x-3=0\end{array} \right.\)
\(⇔\left[ \begin{array}{l}x=0\\2x=3\end{array} \right.\)
\(⇔\left[ \begin{array}{l}x=0\\x=\dfrac32\end{array} \right.\)
Vậy `S={0;3/2}`