Graph the feasible region for the follow system of inequalities by drawing a polygon around the feasible region. Click to set the corner points. $\displaystyle {\left\lbrace\begin{array}{ccc} {x}+{y}&\le&{12}\\-{1}{x}+{y}&\ge&{4}\\{x}&\ge&{0}\\{y}&\ge&{0}\end{array}\right.}$