Using the quadratic formula,
∆=b²-4ac
∆=(3√3)²-4(1)(6)
∆=(9×3)-4(6)
∆=27-24
∆=3
Similarly,
Method 2:
x²-Sx+P=0
where S is the sum of the roots & P is the product of the roots.
x¹+x²= -3√3
x¹x²=6
Solving the system you get the same answers.
Your factored equation can be written in the form of:
(x-x¹)(x-x²)
(x+2√3)(x+√3)