伦簡以下代數分式

1/(a-b)+ 9/(b-a)
= 1/(a-b) - 9/(a-b)
= (1-9)/(a-b)
= -8/(a-b)

1/(a-b)+9/(b-a)
=1/(a-b)-9/(a-b)
=(1-9)/(a-b)
=-8/(a-b)
要知道,其實a-b=b-a,所以只要把符號對換,即加號改為減號,再抽公因子(a-b),便是答案.

2008-01-06 18:32:25 補充：
還有,題目是化簡,而不是"伦"簡.

1/(a-b)+9/(b-a)
=1/(a-b)-9/(a-b)
=1-9/(a-b)
= -(8)/(a-b)

2008-01-05 19:46:17 補充：
1/(a-b) 9/(b-a)=1/(a-b)-9/(-b a)=1/(a-b)-9/(a-b)

1/(a-b)+9/(b-a)
= 1/(a-b) - 9/(a-b) (係b-a度抽個負號出黎)
= (1-9)/(a-b)
=-8/(a-b)