Answer 1

$3) \left \{ {{ \frac{x}{3} - \frac{x}{4}\ \textless \ \frac{x}{6}-1}\atop {6- \frac{x}{2}\ \textgreater \ \frac{x}{4} +3}} \right.$
$\left \{ {{ \frac{4x}{12} - \frac{3x}{12}\ \textless \ \frac{2x-12}{12}}\atop { \frac{24-2x}{4}\ \textgreater \ \frac{x+12}{4} }} \right. \\ \\\left \{ {{ \frac{x}{12} \ \textless \ \frac{2x-12}{12}}\atop { \frac{24-2x}{4}\ \textgreater \ \frac{x+12}{4} }} \right. \\ \\ \left \{ {{x\ \textless \ 2x-12} \atop {24-2x\ \textgreater \ x+12}} \right. \\ \\ \left \{ {{-x\ \textless \ -12} \atop {-3x\ \textgreater \ -12}} \right. \\ \\ \left \{ {{x\ \textgreater \ 12} \atop {x\ \textless \ 4}} \right.$
Система не имеет решений
$4) \left \{ {{ \frac{x}{5} - \frac{2}{3}\ \textless \ \frac{2}{5}- \frac{x}{3} }\atop {\frac{2}{7}+ \frac{x}{3} \ \textgreater \ \frac{x}{7}- \frac{2}{3} }} \right.$
$\left \{ {{ \frac{3x}{15} - \frac{10}{15}\ \textless \ \frac{6}{15}- \frac{5x}{15} }\atop {\frac{6}{21}+ \frac{7x}{21} \ \textgreater \ \frac{3x}{21}- \frac{14}{21} }} \right.$
$\left \{ {{ \frac{3x-10}{15} \ \textless \ \frac{6-5x}{15} }\atop {\frac{6+7x}{21} \ \textgreater \ \frac{3x-14}{21} }} \right. \\ \\ \left \{ {{3x-10\ \textgreater \ 6-5x} \atop {6+7x\ \textgreater \ 3x-14}} \right. \\ \\ \left \{ {{8x\ \textgreater \ 16} \atop {4x\ \textless \ 20}} \right. \\ \\ \left \{ {{x\ \textgreater \ 2} \atop {x\ \textless \ 5}} \right. \\ \\ 2\ \textless \ x\ \textless \ 5$
Ответ. (2;5)

Answer 2

Конечно! Чем могу помочь? Пожалуйста, уточните ваш вопрос, и я с радостью дам вам подробный ответ.