若x2-y2=6,x+y=3,则x-y=

若x2-y2=6,x+y=3,则x-y= 若f(x+y,x-y)=x2-y2,则f(x,y)=, 若x2+4x+y2-6y+13=0则x=?y=? 若x+y=6,x2-y2=48,则x-y=_____ 若x-y=3,x2+y2=13/2,则x+y= 若x+y=3 ,x2-y2=24,则x-y= 若X2+2X+Y2-6Y+10=0,则X+Y=? 若x+y=6,x-y=4则y2-x2 (X+y-3)2+(X-Y+6)2=0,则X2-Y2的值为() 已知：x2-y2=16,x+y=2,求：3x-3y/y2-x2+x2-2xy+y2/x2-y2-x2-x-6/x+2除以(x+y) 已知实数x,y满足3x2+2y2=6x,则x2+y2的最大值是 实数x、y满足3x2＋2y2=6x,则x2＋y2的最大值为 若x2+y2=4,则x-y最大值 x2+y2=4则4x+3y最大值 若X2+Y2-2X-6Y+10=0 ,求（x2-y2)/xy的值 已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值 如题：若4x=5y(y≠0),则x2-y2/y2=?. (x+√(x2+2011))(y+(√y2+2011))=2011,x2-3xy-4y2-6x-6y+58