中二數學題(easy)(10)

2009-01-13 12:49 am
factorize:
x^2 -1 +(1 - x)/3

回答 (5)

2009-01-13 10:25 pm
factorize:
x^2 -1 +(1 - x)/3
=[(x^2-1)*3+(1-x)]*1/3
=(3x^2-3+1-x)*1/3
=(3x^2-x-2)*1/3
=1/3(3x+2)(x-1)
2009-01-13 1:51 am
To 發問者:

請你留意,前面4個答題者,只有#004係做緊factorization。
其他有寫任何「x=...」或者「ans=...」既都錯,因為唔係因式分解。

請大家答題既時候唔好跟風,見人做你就做,
下下跟人地,自己做錯左都唔知。
2009-01-13 1:39 am
x^2 -1 +(1 - x)/3
=(x+1)(x-1) + (1-x)/3
=(x+1)(x-1) - (x-1)/3
=(x-1)(x+1- 1/3)
=(x-1)(x+2/3)
2009-01-13 1:04 am
=[3x^2-3+1-x]/3
=3x^2-x-2
=(x-1)(3x+2)

2009-01-12 17:04:49 補充:
ans= 1 or -2/3
2009-01-13 1:02 am
答案係

factorize:

x^2 -1 +(1 - x)/3

x=-2/3,-1
參考: 自己


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