x²-x-1=0x²-x=1x²-x+1/4=1+1/4(x-1/2)²=5/4x-1/2=±√5/2x=1/2±√5/2=(1±√5)/2x²=(1±2√5+5)/2=(6±2√5)/2=3±√5x³=(1±3√5+15±5√5)/8=(16±8√5)/8=2±√5（1-3/x+2）÷x-1...