xy(x2-y2)=x2+y2 x不等于0 求该等式的最小值
x2-y2=xy,xy不等于0求x2/y2=y2/x2
设x、y为实数,且x2+xy+y2=3,求x2-xy+y2的最大值和最小值.
已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值
X2+y2+2xy+x-y=0,求x的最大值及y的最小值
已知x>y>0,且xy=1,求 (x2+y2)/(x-y)的最小值,
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值
设正实数x,y满足x2-xy+y2=1,求x2-y2的最大值和最小值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知x>y>0且xy=1.求x2+y2/x-y的最小值及此时xy的值
已知xy不等于0,且3x2-2xy-8y2=0,求x/y的值?
已知2x2+5xy-3y2=0且xy不等于0,求x:y的值
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值