f.4 maths

2010-05-13 6:44 am
22. if ax^3 +5x^2 +bx -6 is divisible by 2x^2 +x -3 , find the values of a and b

回答 (2)

2010-05-13 7:04 am
✔ 最佳答案
=================================================

圖片參考:http://img139.imageshack.us/img139/7937/65592696.png


2010-05-12 23:04:27 補充:
http://img139.imageshack.us/img139/7937/65592696.png
2010-05-13 9:20 pm
ax³+5x²+bx−6=2x²+x−3
ax³+5x²+bx−6=(2x+3)(x−1)____(1)
Put x=−3/2 : 9a+4b−14=0___(2)
Put x=1 : a+b−1=0 ___(3)
(2)−4(3): 5a−10=0 ⇒ a=2
∴a=2 , b=−1

2010-05-13 13:23:01 補充:
ax³+5x²+bx−6=(2x²+x−3)·Q(x) ,where Q(x) is the quotient
ax³+5x²+bx−6=(2x+3)(x−1)·Q(x)____(1)


收錄日期: 2021-04-15 23:57:00
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100512000051KK01615

檢視 Wayback Machine 備份