Simplify: 1-(3/x) / 1-(9/x^2)?
回答 (1)
(1 - 3/x ) / ( 1-9/x^2)
1- 3/x = x/x - 3/x = (x-3)/x
1-9/x^2 = x^2/x^2 - 9/x^2 = (x^2-9) /x^2
(1 - 3/x ) / ( 1-9/x^2) = [(x-3)/x] / [ (x^2-9)/x^2]
= [(x-3)/x][ x^2 /(x^2-9)]
= (x-3)x / (x^2-9)
= x(x-3) / ((x-3)(x+3))
= x/ (x+3)
收錄日期: 2021-04-21 01:14:39
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20150123072627AAcLXQr
檢視 Wayback Machine 備份