點計這題?thx
回答 (2)
2007-09-18 5:51 am
✔ 最佳答案
(2x^2 - 5x - 12) / (4x^2 - 1) * [ 2 + 9/(x-4) ]= (2x + 3)(x - 4) / (4x^2 - 1) * [ 2 + 9/(x-4) ]
= (2x + 3)(x - 4) / (4x^2 - 1) * [ (2x - 8 + 9)/(x-4) ]
= (2x + 3)(x - 4) / (4x^2 - 1) * [ (2x + 1)/(x-4) ]
= (2x + 3) / (4x^2 - 1) * [ (2x + 1) ]
= (2x + 3)(2x + 1) / (4x^2 - 1)
= (2x + 3)(2x + 1) / ((2x)^2 - 1)
= (2x + 3)(2x + 1) / [ (2x - 1)(2x + 1) ]
= (2x + 3) / (2x - 1)
2007-09-18 5:55 am
(2x^2 - 5x - 12)/(4x^2-1) X (2+9/(x-4))
=(x-4)(2x+3)/(2x-1)(2x+1) X (2x+1)/(x-4)
=(2x+3)/(2x-1)= 1+(4/(2x-1))
=(x-4)(2x+3)/(2x-1)(2x+1) X (2x+1)/(x-4)
=(2x+3)/(2x-1)= 1+(4/(2x-1))
參考: Me
收錄日期: 2021-04-19 17:12:02
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https://hk.answers.yahoo.com/question/index?qid=20070917000051KK03958