设x,y 满足 x>=0, Y>=0，x+Y

设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y 设x,y满足约束条件x>=0 x>=y 2x-y 设x,y满足约束条件x>=0 y>=x 4x+3y 设变量X,Y满足约束条件{X-Y+3>=0,X+Y>=0,-2 设实数X,Y满足2X+Y-2>=0,X-2Y+4>=0,3X-Y 设Z=x+y,其中实数x,y满足不等式x+2y>=0,x-y 设z=x+y,其中实数x,y满足{x+2y>=0,x-y 变量x,y满足x-2y=0,x 设变量x,y满足约束条件 {x-y≥0,x+y≤1,x+2y≥0},则函数Z=2x+y 的最大值? 设x,y是有理数,并且x,y满足x^2+2x+y^2-4y+5=0求x+y的值 设xy满足约束条件x>=0 y>=0 4x+3y=0 设实数x,y满足y+x^2=0,0