设x,y满足约束条件3x-y-6≤0,x-y+2≥0,x≥0,y≥0,若目标函数z=ax+by(a＞0,b＞0)的最大值为12,则（2/a)+(3/b)的最小值.

设X,Y满足约束条件X+Y 设x,y满足约束条件{x>=0,y>=x,4x+3y 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>1,3x-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x,y满足约束条件x>=0 x>=y 2x-y 设x,y满足约束条件x-4y 设X,Y满足约束条件{X-4Y 设x y 满足约束条件 x≤0 x≤y 2x-y+1≥0 则z=3x+2y的最大值 设变量xy满足约束条件x-y≥0,x+y-2≥0,3x-y-6≤0则目标函数z=2x-y设变量xy满足约束条件x-y≥0,x+y-2≥0,3x-y-6≤0则目标函数z=2x-y的最小值为（ ）. 设x,y满足约束条件:x-y+1≥0,x+y-1≥0,x≤3.则z=2x-3y的最小值为? 设x,y满足约束条件{x-y+5≥0,x+y≥0,x≤3}求z=(x+1)^2-y^2的最大值? 设xy满足约束条件x≥0,x≥y,2x-y≤1,求z=3x+2y的最大值 设xy满足约束条件,1≤x,x+y≥2,y≥3x-6,则z=2x+y最小值 已知实数x,y满足约束条件x+y>3,y 设x,y满足约束条件x+y>=1,x-y>=-1,2x-y