x2-x-1如何因式分解

问题描述:

x2-x-1如何因式分解

x²-x-1=(x-1/2)²-1/4-1
=(x-1/2)²-5/4
=(x-1/2)²-(√5/2)²
=(x-1/2+√5/2)(x-1/2-√5/2)