F.4 maths on Quad.

2007-09-15 6:07 am

If (x-1)(x-5) = (k-1)(k-5), then x=
A. 1 or 5
B. k or 1
C. k or 5
D. k or 6-k

Answer: D
As this is a MCQ, please show the fastest method =]

更新1:

As I said, plz answer the question with the fastest method...

回答 (2)

2007-09-15 6:12 am

✔ 最佳答案

As follows:

圖片參考：http://i117.photobucket.com/albums/o61/billy_hywung/Sep07/Crazyquadratic11.jpg

2007-09-15 13:53:29 補充：
This is already the fastest possible method

參考: My Maths knowledge

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2007-09-15 6:12 am

1眼睇，就知x=k
那麼，如果x唔係 function of k，咁條式，右、左一定唔等於
e.g. x = 1
LHS = (1-1)(1-5) = 0
RHS = (K-1)(K-5)

so the correct answer is D

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