若实数X,Y满足X√1-X=√Y-2+√X-1,求(3X^2+XY-Y^2)/(X^2-XY+Y^2)的值

X√1-X=√Y-2+√X-1
1-X>=0
X-1>=0
所以x＝1
代入,0=√Y-2＋0
所以Y=2
(3X^2+XY-Y^2)/(X^2-XY+Y^2)
＝（3×1^2＋1×2－2^2）/(1^2-1×2+2^2)
＝1/3