用公式法解下列方程快快

3x²-6x-2=0
x1=(6+(36+24)^0.5)/(2*3)
=(6+60^0.5)/6
=(6+2*(15^0.5))/6
=(3+(15^0.5))/3
=1+(5/3)^0.6
x2=(6-(36+24)^0.5)/(2*3)
=(6-60^0.5)/6
=(6-2*(15^0.5))/6
=(3-(15^0.5))/3
=1-(5/3)^0.6
x²+4x+8=4x+11
x²+8=11
x²=3
x1=(3^0.5)
x2=-(3^0.5)
x(2x-4)=5-8x
2x²-4x=5-8x
2x²+4x-5=0
x1=(-4+(16+40)^0.5)/(2*2)
=(-4+56^0.5)/4
=-1+(7/2)^0.5
x2=(-4-(16+40)^0.5)/(2*2)
=(-4-56^0.5)/4
=-1-(7/2)^0.5