列步驟+解釋
solve the following inequalities by the algebraic method.
1.45-x^2-4x>0
math question 20point
2011-03-13 2:59 am
回答 (2)
2011-03-13 3:09 am
✔ 最佳答案
45 – x^2 – 4x > 0x^2 + 4x – 45 < 0(x + 9)(x – 5) < 0Since the product of the 2 terms is negative, 1 is positive and 1 is negative(x + 9>0 and x – 5<0) or(x + 9 < 0 and x – 5 >0) -9 < x < 5 or (x < -9 and x > 5) (rejected)-9 < x < 5
2011-03-13 3:16 am
- X^2 - 4x + 1.45 >0X^2 + 4x - 1.45 <0( X -( -2+√(109/20)) ( X -( -2 -√(109/20)))<0-2 - √(109/20) < X < -2 +√(109/20)
參考: 自己
收錄日期: 2021-04-23 23:22:59
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110312000051KK01112