x2+4y2=2(x-2y)-2,求x,y的值
已知[(x2+y2)-(x-y)2+2y(x-y)]÷4y=1,求4x/4x2-4y2-1/2x+y的值,
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知X2+Y2+8X+6Y+25=0 求代数式X2++XY+4Y2分之X2-4Y2 减X+2Y分之X的值
正整数x,y满足x2-y2=2xy,求x-y/x+y的值
整数x,y满足x2-y2=2xy,求x-y/x+y的值
已知x2+4x+y2-2y+5=0,求x,y的值.
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值
已知方程x2 +y2+4x-2y-4=0,求x2 +y2的最大值
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
已知x2+y2=20,x2+xy-2y2=2(x+2y),求x+y的值
已知实数x,y满足x2+y2-2x+2y=6求x2+y2的最值