Discriminant of 2x2-4x-6=0?

　
Discriminant = b²−4ac
= (−4)²−4(2)(−6)
= 16 + 48
= 64

64

2x²-4x-6 = 0
D = 4²-4(2)(-6) = 16+48 = 64
D> 0
two distinct real roots

2x²-4x-6
= 2(x²-2x-3)
= 2(x-3)(x+1)
x = 3,-1

using quadratic formula
x = (4±√64)/(2*2) = (1/4)(4±8)
= (1/4)(12 or -4)
X = 3, -1

Guess you mean 2x^2 - 4x - 6 = 0
==> x^2 - 2x - 3 = 0
==> the discriminant is (-2)^2 + 12 = 16
Or, directly: (-4)^2 - 4*2*(-6) = 16 + 48 = 64

The thing is, the aspect that matters is to determine the case of
the discriminant being less than 0 (two complex roots)
the discriminant being equal to zero (double root, or root of multiplicity 2)
the discriminant is greater than zero (two real roots)