Question

(x = 2)(3 - 4x) = x² = 4x + 4

Answer 1

\(\left(x-2\right)\left(3-4x\right)=x^2-4x+4\)

\(\Leftrightarrow\left(x-2\right)\left(3-4x\right)-\left(x-2\right)^2=0\)

\(\Leftrightarrow\left(x-2\right)\left(3-4x-x+2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(5-5x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\\\5-5x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\\\x=1\end{matrix}\right.\)

Vậy, \(S=\left\{1;2\right\}\)