因式分解
X^4 － 10X^2 ＋9
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2008-01-18 2:28 am
回答 (3)
2008-01-18 2:34 am
✔ 最佳答案
1) 用十字相乘法,x^2 - 9
x^2 - 1
---------------
-9x^2 - x^2 = -10x^2
所以x^4 - 10x^2 + 9
= ( x^2 - 9 )( x^2 - 1 )
= ( x + 3 )( x - 3 )( x + 1 )( x - 1 ) [ 用恆等式a^2 - b^2 = ( a + b )( a - b )]
2008-01-18 2:34 am
(x^2 - 1)( x^-9)
收錄日期: 2021-04-19 00:18:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080117000051KK02600