First thing to determine is how this parabola opens. Up or down? Or left or right?
*We see that the axis of symmetry is a line parallel to the y-axis; therefore, the axis of symmetry is an x = line, making this an up or down parabola. Now we need to determine how everything else all fits in.
The standard form of this type of parabola is
where p is the distance between the vertex and the focus. If the vertex has a y coordinate of 3, and the focus has a y coordinate of -3, the vertical distance between those 2 numbers is 6. Therefore, p = 6. Filling in then:
Dividing both sides by 24 gives you what you are looking for:
are there answer choices?