Question

一道数学题已知 X^2乘Y^2加X^2加Y^2加1=4乘X乘Y求X,Y

Answer 1

(X²Y²-2XY+1)+(X²-2XY+Y²)=0

(XY-1)²+(X-Y)²=0

以XY-1=0,X-Y=0

X=1,Y=1

或者

x=-1,y=-1