Consider this option:
1. rule: x₀=-b/(2a) and y₀=-D/(4a), where a,b - numbers from y=ax²+bx+c, and D=b²-4ac.
2. according to the rule (y=2x²-8x+6):
x₀=8/4=2 and y₀=-16/8=-2.
Note, y₀ may be calculated, if substitute x₀ into the equation of the curve.
answer: (2;-2)