１９９６年天津市初二数学竞赛有这样一道题：分解因式：（ｘｙ－１）２＋（ｘ＋ｙ－２）（ｘ＋ｙ－２ｘｙ）．本文介绍它的９种分解方法，希望同学们能从中领会到多元和部分含乘积的多项式分解因式的一些方法与技巧．解１展开，按ｘ降幂排列得原式＝（ｙ２－２ｙ＋１）ｘ２－ In the Tianjin Mathematical Competition of Tianjin in 1996, there was a problem: the decomposition factor: (xy-1)2+(x+y-2)(x+y-2xy). This article describes its nine decomposition methods. I hope that my classmates can understand some of the methods and techniques of multivariate and partial polynomial factorization with products. Solution 1 expands and arranges according to the x decreasing power to get the original formula =(y2-2y+1)x2-