已知x2+2xy-2x+y2-2y+1=0,则x+y等于
问题描述:
已知x2+2xy-2x+y2-2y+1=0,则x+y等于
答
x2+2xy-2x+y2-2y+1
=X2+2XY+Y2-2(X+Y)+1
=(X+Y)2-2(X+Y)+1
=(X+Y-1)2=0
X+Y-1=0
X+Y=1