设x2y2-20xy+x2+y2+81=0,求x+y的值
已知x2y2-20xy+x2+81=0求x,y的值
已知xy/x+y=1/3,x2y2/x2+y2=1/5,求xy的值.
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
设x,y为实数,且x2+xy+y2=1,求x2-xy+y2的值的范围
已知x2y2+x2+4xy+13=6x,求x、y的值.
已知x2+y2-4x-10y+29=0求x2y2+2x3y2+x4y2的值
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值
已知x,y为实数,x2y2+x2+4xy+13=6x,求x,y的值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
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x+y=5,x2+y2=13,求代数式x3y+2x2y2+xy3的值.
已知x+y=4,x2+y2=14,求x3y-2x2y2+xy3的值.