Question 1081477
The directrix is  the line, y=2, which you might express as a general point  (x, 2).




One of these methods will work for you:
<a href="https://www.youtube.com/watch?v=Wworlx39KfQ">derive equation of parabola given focus and directrix, vertex not at Origin</a>


<a href="https://www.youtube.com/watch?v=M8LGsQMwwj4">Vertex at the origin,
 derive equation for parabola, given focus and directrix</a>