$d) \frac{x +2}{x -2} - \frac{1}{x} = \frac{2}{x.(x -2)}$ $(ĐKXĐ:$ $x \neq 0; x \neq 2)$
$⇔ \frac{x.(x +2)}{x.(x -2)} - \frac{x -2}{x.(x -2)} = \frac{2}{x.(x -2)}$
$⇒ x.(x +2) - x +2 = 2$
$⇔ x² +2x -x = 0$
$⇔ x² +x = 0$
$⇔ x.(x +1) = 0$
$⇔ \left[ \begin{array}{l}x=0\\x +1=0\end{array} \right. ⇔ \left[ \begin{array}{l}x=0 (Loại)\\x=-1 (t/m đkxđ)\end{array} \right.$
$Vậy$ $S =$ {$-1$}