读图,回答下列问题。
在平面直角坐标系中,抛物线y=﹣x2﹣2x+3与x轴交于A,B两点(A在B的左侧),与y轴交于点C,顶点为D.
Zhang Hai got to the train station ____ ____ yesterday.
已知实数x,y满足y≥1y≤2x-1x+y≤8,则目标函数z=x-y的最小值为( )