幫忙解數學

🎓 學業台小學及中學教育

[匿名]

2006-10-24 6:43 am

3x平方-36x+6=0的兩根為A.B
求(A+B)-A x B=?

回答 (4)

用戶84399

2006-10-24 6:47 am

✔ 最佳答案

3x^2-36x+6 = 0
3(x^2-12x+2) = 0
A+B = 12
AB = 2

(A+B) - AB = 12 - 2 = 10

2006-10-23 22:49:17 補充：
A B = -bAB = c書上面係咁講, 不過佢唔係用AB, 而係用alpha & beta

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[匿名]

2006-10-24 6:53 am

如果無記錯的話,先用韋達定理求出兩根之和 and 兩根之積
A+B = - [(-36) / 3] = 12
A X B = 6 / 3 = 2
所以 ( A+B ) - (A X B) = 12 - 2 = 10

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Chan

2006-10-24 6:48 am

根和 = A + B = - ( -36 ) / 3 = 12
根積 = A * B = 6 / 3 = 2

所以, ( A + B ) - A * B = 12 - 2 = 10

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用戶4478

2006-10-24 6:47 am

唔係好明,可唔可能寫得清楚d...
thanks.

2006-10-23 22:49:31 補充：
(以上回答者及發問者)

參考: 自己

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