What is the equation of the quadratic graph with a focus of (3, 6) and a directrix of y=4

Check the picture below.

one thing to notice is that, the directrix is the horizontal line y = 4, meaning is a vertical parabola, and thus the squared variable is the "x".  The directrix is below the focus point, meaning the parabola is opening upwards, it also means that the "p" distance is positive, in this case  p = 1.

The vertex is always half-way between the focus point and the directrix, in this case is at (3,5).

2.83941151 would be the answer you're looking for! : )

the function makes a strait line horizontally with no x intercept but a y intercept at 9.