Check the picture below.
since the focus point is above the directrix, that simply means the parabola is a vertical one, and therefore the square variable is the "x".
keeping in mind that, there's a distance "p" from the vertex to either the focus point or the directrix, that puts the vertex half-way between those fellows, in this case at 0, right between 1 and -1, as you see in the picture, and the parabola looks like so.
since the parabola is opening upwards, the value for "p" is positive, thus
since the focus point is above the directrix, that simply means the parabola is a vertical one, and therefore the square variable is the "x".
keeping in mind that, there's a distance "p" from the vertex to either the focus point or the directrix, that puts the vertex half-way between those fellows, in this case at 0, right between 1 and -1, as you see in the picture, and the parabola looks like so.
since the parabola is opening upwards, the value for "p" is positive, thus