Question

1+（a-1/1-a)/(1+a/a²-2a+1)

Answer 1

错了

1+（a+1/1-a)/(1+a/a²-2a+1)
=1-(a+1)/(a-1)*[(a-1)²/(a+1)]
=1-(a-1)
=-a+2

追问

那个 1+（a+1/1-a)/(1+a/a²-2a+1)
（a+ 1/1-a) 应该是 a+ 1/1-a 前一个a是个整式

Answer 2

1+（a-1/1-a)/(1+a/a²-2a+1)
=1-(a²-2a+1)/(1+a)
=(-a²+3a)/(a+1)

Answer 3

原式=1 + {[a(1-a)-1] / (1-a)} / {[(a-1)^2 + a] / (a-1)^2}
=1 + [(a - a^2 - 1) / -(a-1)] / [(a^2 - a + 1) / (a-1)^2]
=1 + [(a^2 - a + 1) / (a-1)] × [(a-1)^2 / (a^2 - a + 1)]
=1 + (a-1)
=a

Answer 4

• =1 + {[a(1-a)-1] / (1-a)} / {[(a-1)^2 + a] / (a-1)^2}
  =1 + [(a - a^2 - 1) / -(a-1)] / [(a^2 - a + 1) / (a-1)^2]
  =1 + [(a^2 - a + 1) / (a-1)] × [(a-1)^2 / (a^2 - a + 1)]
  =1 + (a-1)
  =a