x1x2x3.x2011=1x1-x2x3.x2011=1x1x2-x3x4.x2011=1.x1x2.x2010-x2
1个回答

x1x2……x2000-x2001x2002……x2011=1=x1x2……x1999-x2000x2001……x2011

x1x2……x2000+x2000x2001……x2011=x1x2……x1999+x2001x2002……x2011

(x1x2……x1999+x2001x2002……x2011)x2000=x1x2……x1999+x2001x2002……x2011

两边等式一化简得x2000=1

题目就是这样么?还有没有条件了