嗯..超難,只是對於我=.=
12x^3 - 6x^2 -24x +18 =???
pls with steps...:(
超難因式分解..給你全部分如果有人懂
2009-11-25 7:21 pm
回答 (2)
2009-11-25 7:53 pm
✔ 最佳答案
12x^3 - 6x^2 -24x +18 = 6(2x^3 - x^2 - 4x + 3)
= 6(2x^3 - 2x^2 + x^2 - 4x + 3)
= 6[ (2x^2)(x - 1) + (x^2 - 4x + 3) ]
= 6[ (2x^2)(x - 1) + (x - 1)(x - 3) ]
= 6[ (x - 1) ( 2x^2 + x - 3 ) ]
= 6(x - 1)(2x + 3)(x - 1)
= 6(2x + 3)(x - 1)^2
2009-11-25 7:58 pm
其實有好多方法做既
12x^3 - 6x^2 -24x +18 =0
呢題好明顯x=1為其中一個因子
so,
12x^3 - 6x^2 -24x +18 =（x-1）(12x^2+Ax+B) (A,B為任一實數)
12x^3 - 6x^2 -24x +18
=12x^3+Ax^2+Bx-12x^2-Ax-B
=12x^3+(A-12)x^2+(B-A)x-B
對比係數,
B=-18
A=6
12x^3 - 6x^2 -24x +18
=（x-1）(12x^2+6x-18)
=6(x-1)^2(2x+3)
12x^3 - 6x^2 -24x +18 =0
呢題好明顯x=1為其中一個因子
so,
12x^3 - 6x^2 -24x +18 =（x-1）(12x^2+Ax+B) (A,B為任一實數)
12x^3 - 6x^2 -24x +18
=12x^3+Ax^2+Bx-12x^2-Ax-B
=12x^3+(A-12)x^2+(B-A)x-B
對比係數,
B=-18
A=6
12x^3 - 6x^2 -24x +18
=（x-1）(12x^2+6x-18)
=6(x-1)^2(2x+3)
參考: myself
收錄日期: 2021-04-21 22:06:19
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https://hk.answers.yahoo.com/question/index?qid=20091125000051KK00350