Find the range of the values of k if each of the following quadratic equations has no real roots .
(k+2)x^2-4x-5=0
中四Math .....一問
2007-09-22 1:13 am
回答 (2)
2007-09-22 8:41 pm
✔ 最佳答案
Since (k+2)x^2 - 4x - 5 = 0 has no rootsDiscriminant < 0
Therefore,
b^2 - 4ac < 0
In this case, a=k+2, b=-4, c=-5
(-4)^2 - 4(k+2)(-5) < 0
16 + 20(k+2) < 0
16 + 20k + 40 < 0
20k + 56 < 0
20k < -56
k < -56/20
k < -14/5
參考: Me
2007-09-22 1:25 am
Discriminant=16-4(k+2)(-5)<0
16+20(k+2)<0
k+2<-4/5
k<-14/5
16+20(k+2)<0
k+2<-4/5
k<-14/5
收錄日期: 2021-04-13 19:03:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070921000051KK02022