(1) $\leftrightarrow \dfrac{x}{4}+\dfrac{5}{4}-\dfrac{3x}{7} < x-\dfrac{x}{3}+\dfrac{2}{3}$
$\leftrightarrow -\dfrac{71}{84}x < -\dfrac{7}{12}$
$\leftrightarrow x > \dfrac{49}{71} \approx 0,69$
(2) $\leftrightarrow \dfrac{6x}{4}+\dfrac{5}{4}+\dfrac{x}{14}-\dfrac{1}{7} \le 7$
$\leftrightarrow \dfrac{11}{7}x \le \dfrac{165}{28}$
$\leftrightarrow x \le \dfrac{15}{4}=3,75$
Vậy $S=$ { $1 ; 2 ; 3$}