首页 > 留学知识库

问题: a^2/a-1减1/1-a减a减1

解答:

a^2/(a-1)-1/(1-a)-a-1
=a^2/(a-1)+1/(a-1)-(a+1)
=a^2/(a-1)+1/(a-1)-(a^2-1)/(a-1)
=(a^2+1-a^2+1)/(a-1)
=2/(a-1)