在实数范围内分解因式：x2+x-1=．

Question

在实数范围内分解因式：x²+x-1=______．

Answer 1

x²+x+(1)/(4)−(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)]
=（x+(1)/(2)+(√(5))/(2)）（x+(1)/(2)−(√(5))/(2)）．