展開多項式：
1)(x-3)(2x+1)(3x+2)=?
因式分解：
1)-b^3+b^2-9b=?
2)4(r-d)^2-2(r-d)=?
3)(a-2)^2-p(a-2)=?
有幾條數學唔識做，邊個可以教我呀！＝．＝
2006-10-15 4:18 am
回答 (2)
2006-10-15 4:40 am
1. (x-3)(2x+1)(3x+2)
= (2x^2 + x - 6x - 3)(3x + 2)
= (2x^2 - 5x - 3)(3x + 2)
= 6x^3 + 4x^2 - 15x^2 - 10x - 9x - 6
= 6x^3 - 11x^2 - 19x - 6
因式分解：
1. -b^3+b^2-9b
= (-b)(b^2 - b + 9)
2. 4(r-d)^2-2(r-d)
= [2(r-d)]^2 - 2(r-d)
= 2(r-d)[2(r-d) - 1]
3. (a-2)^2-p(a-2)
= (a-2)(a-2-p)
= (2x^2 + x - 6x - 3)(3x + 2)
= (2x^2 - 5x - 3)(3x + 2)
= 6x^3 + 4x^2 - 15x^2 - 10x - 9x - 6
= 6x^3 - 11x^2 - 19x - 6
因式分解：
1. -b^3+b^2-9b
= (-b)(b^2 - b + 9)
2. 4(r-d)^2-2(r-d)
= [2(r-d)]^2 - 2(r-d)
= 2(r-d)[2(r-d) - 1]
3. (a-2)^2-p(a-2)
= (a-2)(a-2-p)
2006-10-15 4:23 am
^這符號是甚麼意思?
收錄日期: 2021-04-12 18:09:52
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061014000051KK05186