If X^2 – X = 4, then (1 – 2X)^2 = ?
the ans. = 17.
Pls. show your step,
Thx. a lot.
F2 Maths. (2)
2010-02-27 6:03 pm
回答 (1)
2010-02-27 6:52 pm
✔ 最佳答案
(1 – 2X)^2= (2x - 1)^2
= (2x)^2 - 2(2x)(1) + 1^2
= 4x^2 - 4x + 1
= 4(x^2 - x) + 1
By given that x^2 - x = 4 ,
= 4(4) + 1
= 17
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100227000051KK00345