4x(x-2) = 3(2-x)
⇔ 4x2 - 8x = 6 - 3x
⇔ 4x2 - 8x + 3x - 6 = 0
⇔ 4x(x-2) + 3(x-2) = 0
⇔ (x-2)(4x+3) = 0
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\4x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\frac{-3}{4}\end{matrix}\right.\)
Vậy : \(S=\left\{2;\frac{-3}{4}\right\}\)