There are three girls, Olivia, Sarah, and Grace. Olivia gives her pen to Sarah. Sarah gives her pen to Olivia and Grace. Grace gives her pen to Olivia. Organize the given data in a matrix.

Step-by-step explanation:

Sarah has one pen

Olivia has two pens

Grace has zero pens

Step-by-step explanation:

We are given the directrix equation and the location of the focus as a means to determine what the vertex (h, k) of the parabola is.  Since the directrix is a horizontal line AND since the directrix is below the focus, AND since the parabola ALWAYS wraps itself around the focus, this is a positive parabola of the form

We also know that since the vertex is directly in between the focus and the directrix, it has coordinates of (0, 0).  So h = 0 and k = 0.

By definition, p is the distance between the vertex and the focus (and also the vertex and the directrix since they are both the same).  Therefore, p = 4.

Filling in our equation with those values gives us

and solving for y gives us