solve this equation 2-2-4x-6=0, using the four methods?

　
Regarding your comment to Mike G, it's not a matter of not being able to solve using the four methods. It a matter of not being a quadratic equation at all, most probably due to a typo.

I assume you meant: 2x^2 − 4x − 6 = 0

Factoring:
2x² − 4x − 6 = 0
2 (x² − 2x − 3) = 0
2 (x − 3) (x + 1) = 0
x = 3, x = −1

Completing the square:
2x² − 4x = 6
x² − 2x = 3
x² − 2x + 1 = 3 + 1
(x − 1)² = 4
x − 1 = ± 2
x = 1 ± 2
x = 3, x = −1

Quadratic formula
x = (−b ± √(b²−4ac)) / (2a), where a = 2, b = −4, c = −6
x = (4 ± √(16−4·2·−6)) / (2·2)
x = (4 ± √64) / 4
x = (4 ± 8) / 4
x = 1 ± 2
x = 3, x = −1

Graphing:
http://www.wolframalpha.com/input/?i=y+%3D+2x%5E2+-+4x+-+6

Equation is not a quadratic.

The equation is incorrect.

2x^2 - 4x - 6 = 0
2(x^2 - 2x - 3) = 0
2(x - 3)(x + 1) = 0
2(x - 1)^2 - 8 = 0
Solutions:
x = -1
x = 3