x方-x-1 因式分解

题目

x方-x-1 因式分解

答案

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