问题
解答题
x2-{x2-[x2-（x2-1）-1]-1}-1．
答案
x2-{x2-[x2-（x2-1）-1]-1}-1
=x2-{x2-[x2-x2+1-1]-1}-1
=x2-{x2-x2+x2-1+1-1}-1
=x2-x2+x2-x2+1-1+1-1
=0．
搜题请搜索小程序“爱下问搜题”
x2-{x2-[x2-（x2-1）-1]-1}-1．
x2-{x2-[x2-（x2-1）-1]-1}-1
=x2-{x2-[x2-x2+1-1]-1}-1
=x2-{x2-x2+x2-1+1-1}-1
=x2-x2+x2-x2+1-1+1-1
=0．