$$-y\ge7; Y\ge3x-10$$
$x\leq \frac{y+10}{3}$
$y\geq 7$
$\left\{\begin{matrix}y\geq 3x-10\text{, }&x\geq \frac{17}{3}\\y\geq 7\text{, }&x<\frac{17}{3}\end{matrix}\right.$
