a very very hard question

问题描述:

a very very hard question
8x^3+1 (分解因式)

用立方和差公式:a^3+b^3=(a+b)(a^2-ab+b^2)
a^3-b^3=(a-b)(a^2+ab+b^2)得8x^3+1 =(2x+1)(4x^2-2x+1)