What is the distance between the focus of the parabola y = - 12x and the directrix?

What is the distance between the focus of the parabola y = - 12x and the directrix?

In the parabola y ^ 2 = - 2px, the focus is (- P / 2,0), and the equation of Quasilinear is x = P / 2
We get P = 6
So the focus of the parabola y ^ 2 = - 12x is (- 3,0) and the collimator is x = 3
So the distance from the focus of the parabola y = - 12x to the collimator is p = 6