(x-3)^2 - 4x^2
唔該曬!!!
F.2 maths.....!!!!趕!!!
2007-03-09 2:55 am
回答 (3)
2007-03-09 3:01 am
✔ 最佳答案
(x - 3)^2 - 4x^2= (x - 3)^2 - (2x)^2
= (x - 3 - 2x)(x - 3 + 2x)
= (-x - 3)(3x - 3)
= -(x + 3)3(x - 1)
= -3(x + 3)(x - 1)
2007-03-08 19:02:16 補充：
THe above answer is wrong because 4x^2 does not equals to (4x)^2 but 4*x^2
參考: Me
2007-03-09 3:11 am
我不明白閣下究竟想問什麼
要factorisation還是直接拆括號
我兩者皆做:
因式分解:
(x-3)²-4x²
=(x-3)²-(2x)²
=(x-3+2x)(x-3-2x) (Because (a+b)(a-b)=a²-b²)
=-(3x-3)(x+3)
拆括號:
(x-3)²-4x²
=(x²-6x+9)-4x²
=x²-6x+9-4x²
=-3x²-6x+9
2007-03-08 19:12:58 補充：
不好意思,差了一點:-(3x-3)(x十3)=-3(x-1)(x十3)二樓:閣下錯了,x-3絕不等於x²-9
要factorisation還是直接拆括號
我兩者皆做:
因式分解:
(x-3)²-4x²
=(x-3)²-(2x)²
=(x-3+2x)(x-3-2x) (Because (a+b)(a-b)=a²-b²)
=-(3x-3)(x+3)
拆括號:
(x-3)²-4x²
=(x²-6x+9)-4x²
=x²-6x+9-4x²
=-3x²-6x+9
2007-03-08 19:12:58 補充：
不好意思,差了一點:-(3x-3)(x十3)=-3(x-1)(x十3)二樓:閣下錯了,x-3絕不等於x²-9
收錄日期: 2021-04-13 13:45:44
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https://hk.answers.yahoo.com/question/index?qid=20070308000051KK03014