| x-4| > 5 ans is ?
仲有有冇不等式會兩邊同時有絕對值?
數學題....
2007-12-18 8:32 pm
回答 (2)
2007-12-18 8:44 pm
✔ 最佳答案
1. | x-4 | > 5
x-4 < -5 or x-4 > 5
x < -1 or x > 9
2.
應該有.
例如:
|2x-1| > |x-5|
(2x-1)^2 > (x-5)^2
[(2x-1)+(x-5)][(2x-1)-(x-5)] < 0
(3x-6)(x+4) <0
(x-2)(x+4)<0
-4 < x < 2
有錯請指正!
參考: My Maths knowledge
2007-12-18 8:46 pm
|x-4| > 5
==> x-4 > 5 or - (x-4) > 5
==> x > 9 or x-4 < -5
==> x > 9 or x < -1 (answer)
==> x-4 > 5 or - (x-4) > 5
==> x > 9 or x-4 < -5
==> x > 9 or x < -1 (answer)
收錄日期: 2021-04-13 14:44:34
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