Question

先化简，再求值：（1-【1/（a-1）】）÷【（a²-4a+4）/（a²）】，其中a=-1

（1-【1/（a-1）】）÷【（a²-4a+4）/（a²-a）】，其中a=-1，不要意思 题目打错了

Answer 1

=(a-1-1)/(a-1)÷(a-2)^2/a^2
=(a-2)/(a-1)÷(a-2)^2/a^2
=a^2/(a-1)*(a-2)
=1/(-2)*(-3)
=1/6

追问

题目打错了，不要意思麻烦你从新看一看

追答

=(a-1-1)/(a-1)÷(a-2)^2/a(a-1)
=(a-2)/(a-1)÷(a-2)^2/a(a-1)
=a/(a-2)
=-1/(-3)
=1/3