(6)设 $x, y$ 满足 $\left\{\begin{array}{l}2 x+y \geq 4, \\ x-y \geq 1, \\ x-2 y \leq 2,\end{array}\right.$ 则 $z=x+y$
参考答案B
2009_老新课标卷 (2009·文)
(6)设 $x, y$ 满足 $\left\{\begin{array}{l}2 x+y \geq 4, \\ x-y \geq 1, \\ x-2 y \leq 2,\end{array}\right.$ 则 $z=x+y$