x2+y2+xy-3y+3=0

若X2+xy-2y2=0,则（x2+3xy+y2)/x2+y2=? x2+y2+xy-3y+3=0 解方程组 ｛3x2-y2=8 {4x2+12xy+9y2=1 {x2+2xy+y2-4=0 x2+xy+y2=4 4x2-9y2=0 x2-2xy+y2-1=0还有{x2+y2=4xy-y2+4=0x2-----x的平方 y2------y的平方 还有{2x-3y=12x2-3xy+y2-4x+3y-3=0 已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值 x2-2xy-3y2=0,其中x,y均不为零,求（y-x）/x2-xy/2x-y-y2/xy-x x的平方+ xy-2y的平方=0,则(X2+3Xy+Y2)/(X2+Y2)=__x的平方+ xy-2y的平方=0,则(X2+3Xy+Y2)/(X2+Y2)=__其中(X2+3Xy+Y2)/(X2+Y2)=__的2为平方 已知非零实数x,y满足:x2+xy-2y2=0,求(x2+3y+y2)/(x2+y2)的值 x2-4y2-3xy+y+x 解方程组①x2-y2=3x+3y②x2-xy+y2=27 如果2/x=3/y,那么x2-2xy+3y2/7x2-y2? 解方程组 x2 -2xy -y2 =1 2x2 -5xy -3y2 =0 x2+3xy+2y2=0,则x2+y2/xy x+y=3,xy=-5,x2+y2=19,x2-xy+y2=24,求x-y 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） x2+2xy+y2-9=0 (x-y)2-3(x-y)+2=0 已知x2-2xy-3y2=0求(2x+3y)/2y x2+y2+xy-3y+3=0,求x.y 若|x-y|+（y+3）2=0,则x2+y2-2xy=