4x^2-12x-1=0
4x^2-12x+9-10=0
4(x^2-3x+9/4)=10
x^2-3x+9/4=10/4
(x-3/2)^2=10/4
x-3/2=√10/2
x=(√10+3)/2
或
x-3/2=-√10/2
x=(3-√10)/2
4x^2-12x-1=0
4x^2-12x=1
4(x^2-3x)=1
x^2-3x=1/4
x^2-3x+9/4=1/4+9/4
(x-3/2)^2=5/2
x-3/2=(√10)/2或x-3/2=-(√10)/2
x=(√10+3)/2或x=(-√10+3)/2