請詳細步教我計以下二條,最好加講解,我唔識劃表同唔識點睇做答案.
Solve each of the following quadratic inequalities by using tabulation method and represent the solutions on the number line.
a) (3x+4)(x-1)>=0
b) 5x^2+8x<4
急!F5 inequalities unknown 2q1
2012-09-30 4:33 am
回答 (1)
2012-09-30 7:04 pm
✔ 最佳答案
(a) (3x + 4)(x - 1) = 0x = - 4/3 or 1
Case I
When x < - 4/3
(3x + 4) < 0
(x - 1) < 0
so (3x + 4)(x - 1) > 0 acceptable.
Case II
- 4/3 < x < 1
(3x + 4) > 0
(x - 1) < 0
so (3x + 4)(x - 1) < 0 not acceptable.
Case III
x > 1
(3x + 4) > 0
(x - 1) > 0
so (3x + 4)(x - 1) > 0 acceptable.
Answer : x < - 4/3 or x > 1.
(b) 5x^2 + 8x - 4 < 0
(5x - 2)(x + 2) < 0
Using the same method as in (a)
Answer : - 2 < x < 2/5.
收錄日期: 2021-04-13 19:00:38
原文連結 [永久失效]:
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