分式混合运算：a-1分之a+1-a²-2a+1分之a除以a分之1
问题描述：
分式混合运算：a-1分之a+1-a²-2a+1分之a除以a分之1
答
=(a+1)/(a-1)-a/(a-1)²×a
=(a+1)(a-1)/(a-1)²-a²/(a-1)²
=(a²-1-a²)/(a-1)²
=-1/(a²-2a+1)