請教國二數學上，若x-1/y=3，xy+1/xy=39，則y-1/x=?
回答 (1)
2016-10-02 8:45 am
✔ 最佳答案
xy + 1/(xy) = 39xy - x/x - y/y + 1/(xy) = 39 - x/x - y/y
x(y - 1/x) - (1/y)(y - 1/x) = 37
(x - 1/y) (y - 1/x) = 37
3 (y - 1/x) = 37
y - 1/x = 37/3
收錄日期: 2021-04-24 23:36:14
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20161002001521AA0oIit