已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值
已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值
设正实数x,y满足x2-xy+y2=1,求x2-y2的最大值和最小值
设x、y为实数,且x2+xy+y2=3,求x2-xy+y2的最大值和最小值.
已知非零实数x,y满足:x2+xy-2y2=0,求(x2+3y+y2)/(x2+y2)的值
已知实数x,y满足1≤x2+y2≤4,求f(x,y)=x2+xy+y2的最大值和最小值
实数xy满足x2+y2+2x-4y+1=0,则x2+y2-2x+1的最小值为
已知x、y是实数且满足x2+xy+y2-2=0,设M=x2-xy+y2,则M的取值范围是______.
已知实数x、y满足2x2-7xy+3y2=0,求x:y
如果实数x y 满足x2+y2=1,那么(1-xy)(1+xy)的最小值和最大值
若实数x,y满足|xy|=1,则x2+4y2的最小值为______.
已知实数xy满足x2+y2=4.则y+3/x+1的取值范围为
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值