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问题: 一道初中分解因式题

(xy-1)的平方+(x+y-2)(x+y-2xy)

解答:

(XY-1)^2+(X+Y-2)(X+Y-2XY)
=(XY)^2-2XY+1+(X+Y)^2-2XY(X+Y)-2(X+Y)+4XY
=(XY)^2+2XY+1+(X+Y)^2-2(XY+1)(X+Y)
=(XY+1)^2-2(XY+1)(X+Y)+(X+Y)^2
=(XY+1-X-Y)^2