因式分解!

As follows, we use the method synthetic division to factorize the question.


圖片參考：http://i182.photobucket.com/albums/x4/A_Hepburn_1990/1546.jpg?t=1184659999


2007-07-18 18:46:47 補充：
synthetic division 係綜合除法。你會喺純粹數學中學到的。

你必須在計算前認識一條公式
n是奇數
x^n+y^n=(x+y)(x^(n-1) - x^(n-2)y + x^(n-3)y^2 - .....+y^(n-1))減加減加地循環着

x^5+y^5
=(x+y)(x^4-x^3y+x^2y^2-xy^3+y^4)

x^7+y^7
=(x+y)(x^6-x^5y+x^4y^2-x^3y^3+x^2y^4-xy^5+y^6)