问题描述: (xy-1)^2+(x+y-2xy)(x+y-2) 因式分解,用换元法做,设t 1个回答 分类:数学 2014-09-23 问题解答: 我来补答 设xy=m,x+y=n原式=(m-1)^2+(n-2m)(n-2)=m^2-2m+1+n^2-(2+2m)n+4m=(m-n)^2+2(m-n)=(m-n)(m-n+2)=(xy-x-y)(xy-x-y+2) 再问: t 再答: 设x+y=t原式=(xy-1)^2+(t-2xy)(t-2)=(xy)^2-2xy+1+t^-2xyt-2t+4xy=(xy-t)^2+2(xy-t)=(xy-t)(xy-t+2)=(xy-x-y)(xy-x-y+2) 展开全文阅读