有條數唔識計
回答 (2)
2010-12-19 3:03 am
✔ 最佳答案
f(x)=(x+k)(x-1)-2x. Sub. x=k, f(k)=(k+k)(k-1)-2k=2k(k-1)-2k=2k^2-4kUsing the information f(k)=k^2-3,
2k^2-4k = k^2-3
k^2-4k+3=0
(k-1)(k-3)=0
k=1 or k=3
2010-12-19 3:07 am
f(k)=(k+k)(k-1)-2k
k^2-3=2k(k-1)-2k
k^2-3=2k^2-2k-2k
-3=k^2-4k
0=k^2-4k+3
k=3 or 1
k^2-3=2k(k-1)-2k
k^2-3=2k^2-2k-2k
-3=k^2-4k
0=k^2-4k+3
k=3 or 1
參考: me~
收錄日期: 2021-04-26 14:03:04
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20101218000051KK00932