Graph the system of inequalities. Tell whether the system is bounded or unbounded and list each corner point. $$\left\{ \begin{array}{r@{}r@{}r@{}r} x & \ge & 4 & \cr y & \le & 15 & \cr y & \ge & x \cr x & \ge & 0 & \cr y & \ge & 0 & \end{array} \right.$$

Region is: Input bounded or unbounded .

Corner Points:
If there is more than one corner point, type the points separated by a comma (i.e.: (1,2),(3,4)).