x(1 - x) - (x - 1) = 0
\(\Leftrightarrow\) x(1 - x) + (1 - x) = 0
\(\Leftrightarrow\) (1 - x)(x + 1) = 0
\(\Leftrightarrow\left[{}\begin{matrix}1-x=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)
Vậy S = {1; -1}
Chúc bn học tốt!!