x-1分之x的立方-x的平方-x-1=

=x³/(x-1) -(x²+x+1)
=x³/(x-1) -(x-1)(x²+x+1)/(x-1)
=x³/(x-1) -(x³-1)/(x-1)
=1/(x-1)
再问： 对吗 感觉跟我题目不一样啊
再答： 对的
x-1分之x的立方 -x的平方-x-1
=x³/(x-1) -(x²+x+1) 将后面的三项放到带有负号的括号里
=x³/(x-1) -(x-1)(x²+x+1)/(x-1) 后面部分通分
=x³/(x-1) -(x³-1)/(x-1) 计算后面的分子
=1/(x-1) 合并