If the coefficient of x(power 4 ) in the wxpansion of (2-3px)(4x(power4)+5x(power3)-x) is 38,find the value of p.
要步驟
數學一問(中一)真係要幫,要步驟
2011-04-19 6:41 am
回答 (2)
2011-04-19 10:08 am
✔ 最佳答案
(2 - 3px)(4x^4 + 5x^3 - x)= 8x^4 + 10x^3 - 2x - 12px^5 - 15px^4 + 3px^2 (折括弧)
= -12px^5 + (8-15p)x^4 + 10x^3 + 3px^2 - 2x
since the coefficient of x^4 =38,
8 - 15p = 38
-15p = 30
p = -2
參考: me
2011-04-19 8:49 am
收錄日期: 2021-04-23 20:46:53
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110418000051KK01391