用公式法解一元二次方程X^2+x-1＝0

x²+x-1=0(x²+x+1/4)-1/4-1=0(x+1/2)²-5/4=0(x+1/2)²=5/4x+1/2=±(√5)/2x=±(√5)/2-1/2x=[±(√5)-1]/2x1=[(√5)-1]/2，x2=-[(√5)+1]/2