x2-y2=xy,xy不等于0求x2/y2=y2/x2
x2-y2=xy,xy不等于0求x2/y2=y2/x2
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/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
X2+Y2+XY=2,求X2+Y2-XY取值范围
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知x2-xy=-3,2xy-y2=-8,求2x2+4xy-3y2的值.
已知x2+xy=-3,xy+y2=7,试求:x2+2xy+y2的值.
已知x2-xy=3,xy-y2=-5,试求代数式x2+2xy-3y2的值.
已知x2-xy=21,xy-y2=-12,分别求式子x2-y2与x2-2xy+y2的值.
已知x2+y2=7,xy=-2,求5x2—3xy—4y2—11xy—7x2+2y2的值
已知x2+y2 =7,xy=-2.求5x2 -3xy-4y2 -11xy-7x2 +2y2