设变量x,y满足约束条件 x+y≤a x+y≥8 x≥6且不等式x+2y≤4恒成立,则实数a的取值范围

设变量x,y满足约束条件x-y>-1,x+y>1,3x-y 设X,Y满足约束条件X+Y 已知变量x,y满足约束条件1 设变量X,Y满足约束条件{X-Y+3>=0,X+Y>=0,-2 设变量x,y满足约束条件:x-y+3>=0 x+y>=0 -2 设变量x y满足约束条件x-y≥-1 x+y≥1 2x-y≤1 z=(x-2y)/(x+y)的最大值 已知变量x,y满足约束条件｛x+y 已知变量x,y满足约束条件｛x+y 若变量x y满足约束条件{x+y 设变量x,y满足约束条件x-y>=-1,x+y>=1,3x-y 设变量x,y满足约束条件y≤x,x+y≥2,y≥3x-6,则目标函数z=2x+y的最小值 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? 设变量x,y满足约束条件2x+y≤2,x≥y,y≥-1,则z=-y+3x的最大值为? 设变量x,y满足约束条件y>=0.x-y+1>=0.x+y-3 设变量满足约束条件x+y≥3,x-y≥-1,2x-y≤3,则目标函数z=2x+2y最小值? 设变量x,y满足x+y 变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y