设y=6x²-7x
原方程即y²-2y-3=0
(y-3)(y+1)=0
y1=3,y2=-1
当y=3时,6x²-7x=3
(3x+1)(2x-3)=0
x1=-1/3,x2=3/2
当y=-1时, 6x²-7x=-1
6x²-7x+1=0
(6x-1)(x-1)=0
x3=1/6,x4=1