x(x-5)(x+1)>0
如果有三個
應該點樣做???
同埋如果 x(x-5)(x+1)<0
又應該點做
Thx
inequality 10分
2008-04-06 5:18 pm
回答 (1)
2008-04-06 5:59 pm
✔ 最佳答案
First of all, the roots of x ( x - 5) (x + 1) = 0 are x = -1, 0 and 5.Then we can list out the range of x in table form as follows:
圖片參考：http://i117.photobucket.com/albums/o61/billy_hywung/Apr08/Crazyineq1.jpg
So, for x ( x - 5) (x + 1) > 0, we have -1 < x < 0 or x > 5
For x ( x - 5) (x + 1) < 0, we have x < -1 or 0 < x < 5
(用了正負數相乘的結果)
參考: My Maths knowledge
收錄日期: 2021-04-23 17:54:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080406000051KK00542