设x,y满足条件3x-y-6=0,x>=0y>=0,若目标函数z=ax+by(a>0,b>0)的最大值为12则2/a+3/b 的最小值是?答案是25/6.我知道两直线交点为(4,6) ∴4a+6b=12 即a=（6-3b）/2为什么把a代进去2/a+3/b=4/(6-3b)+3/b>=2根号（12/6b-3b^

设x、y满足条件x-y+5>=0,x+y>=0,x 设x.y满足条件y>=0.X-Y+1>=0.x+y-3 设X,Y满足条件x-y+2>=0,x+y-4>=0,2x-y-5 设变量x.y满足条件3x+2y 设z=2y-2x+4,式中x,y满足条件a,0 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z=x-y,式中变量x和y满足条件x+y-3≥0,x-2y≥0,则z的最小值为 当x,y满足条件x>=0,y 设方程组3x+y=k+1 x+3y=3的解xy满足条件0 设方程组3x+y=k+1 x+3y=3的解xy满足条件0 设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y 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 设实数X,Y满足2X+Y-2>=0,X-2Y+4>=0,3X-Y 设实数x、y同时满足条件：4x^－9y^=36,且xy 设实数x,y满足 x>=0 x-2y>=0 x-y-2 设x,y满足约束条件x>=0 x>=y 2x-y