$\text{ĐKXĐ: x $\neq$ 0; x $\neq$ 1 }$
$\text{Từ PT (1) ⇔ $\dfrac{(x +1).(x -1) -2x}{x.(x -1)} = \dfrac{2x +3}{x.(x -1)}$}$
$⇒ (x +1).(x -1) -2x = 2x +3$
$⇔ x² -1 -2x -2x -3 = 0$
$⇔ x² -4x -4 = 0$
$⇔ (x -2)² -8 = 0$
$⇔ (x -2 -√8).(x -2 +√8) = 0$
$⇔ \left[ \begin{array}{l}x -2 -√8=0\\x -2 +√8=0\end{array} \right. ⇔ \left[ \begin{array}{l}x=2 +√8\\x=2 -√8\end{array} \right.$ $\text{(T/m ĐKXĐ)}$
$\text{Vậy S = {2 +√8; 2 -√8}}$