x³-9x²+27x-27怎麼算？有關乘法公式 因式分解的 不知道全部過程....?
回答 (4)
2017-07-27 7:08 pm
✔ 最佳答案
Solf(x)=x^3－9x^2+27x－27
f(3)=27－81+81－27=0
x－3為一因式
x^3－9x^2+27x－27
=(x^3－3x^2)+(－6x^2+18x)+(9x－27)
=x^2(x－3)－6x(x－3)+9(x－3)
=(x^2－6x+9)(x－3)
=(x－3)^2(x－3)
=(x－3)^3
or
x^3－9x^2+27x－27
=x^3+3*x^2*(－3)+3*x*(－3)^2+(－3)^3
=(x－3)^3
2017-07-27 7:54 pm
X³ - 9x² + 27x - 27
= X³ - 3 x²(3) + 3 x(3²) - (3³)
= (x-3)³ <------------- 乘法公式《 (a - b)³ = a³ - 3 a²b + 3 ab² - b³ 》
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乘法公式 :-
========
(a + b)³ = a³ + 3 a²b + 3 ab² + b³
(a - b)³ = a³ - 3 a²b + 3 ab² - b³
= X³ - 3 x²(3) + 3 x(3²) - (3³)
= (x-3)³ <------------- 乘法公式《 (a - b)³ = a³ - 3 a²b + 3 ab² - b³ 》
--- * --- * --- * --- * --- * --- * --- * --- * --- * --- * --- * --- *--- * --- * --- * ---
乘法公式 :-
========
(a + b)³ = a³ + 3 a²b + 3 ab² + b³
(a - b)³ = a³ - 3 a²b + 3 ab² - b³
2017-07-27 7:15 pm
x^3-9x^2+27x-27
=x^3-27-9x^2+27x
=(x-3)(x^2+3x+9)-(9x^2-27x)
=(x-3)(x^2+3x+9)-9x(x-3)
=(x-3)(x^2+3x+9-9x)
=(x-3)(x^2-6x+9)
=(x-3)(x-3)^2
=(x-3)^3
=x^3-27-9x^2+27x
=(x-3)(x^2+3x+9)-(9x^2-27x)
=(x-3)(x^2+3x+9)-9x(x-3)
=(x-3)(x^2+3x+9-9x)
=(x-3)(x^2-6x+9)
=(x-3)(x-3)^2
=(x-3)^3
2017-07-27 8:27 pm
抽出(x+...)
收錄日期: 2021-04-18 17:26:41
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20170727102240AAenZUU