The equation would be:
3x2-4x-2=0, divide through by 3:
x2-4x/3-2/3=0,
x2-4x/3=2/3, complete the square:
x2-4x/3+4/9=2/3+4/9=10/9,
(x-2/3)2=10/9,
x-2/3=±√10/3,
x=2/3±√10/3, x=1.721 or -0.387 approx.
The same result can be obtained using the formula:
x=(4±√(16+24))/6=(4±√40)/6=(4±2√10)/6=(2±√10)/3.