Объяснение:

[tex]\left \{ {{\frac{y}{6} +\frac{y}{5} > 3\ |*30} \atop {24-\frac{y}{7} > 0\ |*7}} \right. \ \ \ \ \left \{ {{5*y+6*y > 3*30} \atop {24*7-y > 0}} \right. \ \ \ \ \left \{ {{11y > 90\ |:11} \atop {y < 168}} \right. \ \ \ \ \left \{ {{y > 8\frac{2}{11} } \atop {y < 168}} \right. \ \ \ \ \Rightarrow\\x\in[9 ;167]\ , x\in \mathbb N.[/tex]