已知O为坐标原点,A(1,2),点P的坐标(x,y)满足约束条件则z=的最大值为( )
A.-2 B.-1 C.1 D.2
设x,y∈R,a>1,b>1,若ax=by=3,a+b=2,则的最大值为( )
A. B.1 C. D.2
设x,y,z均为正整数,满足x-2y+3z=0,则的最小值是________.
设x,y满足约束条件向量a=(y-2x,m),b=(1,-1),且a∥b,则m的最小值为________.
若正数x,y满足2x+y-3=0,则的最小值为________.
实数x,y满足则z=2x+y的最小值为( )
A.-2 B.2 C.3 D.4