x²-2x-1=0 x²+x-1=0 x²+8x=9 4x²-4x-1=0 x²-2x-2=0

x²-2x-1=0 x²+x-1=0 x²+8x=9 4x²-4x-1=0 x²-2x-2=0
x²-2x-1=0 x²+x-1=0 x²+8x=9 4x²-4x-1=0 x²-2x-2=0

x²-2x-1=0 x²+x-1=0 x²+8x=9 4x²-4x-1=0 x²-2x-2=0
楼主要问什么?

x²-2x-1=0
x=[2±√(2²+4)]/2=1±√2

x²+x-1=0
x=[-1±√(1²+4)]/2=(-1±√5)/2

x²+8x=9
x²+8x-9=0
(x-1)(x+9)=0
x=1,x=-9

4x²-4x-1=0

x²-2x-2=0
x=[2±√(2²+4×2)]/2=1±√3

楼主要问什么？

1.x=1±√2
2.x=-1/2±√5/2
3.x=1 x=-9
4.x=(1±√2）/2
5.x=1±√3