(y-k)² = 4p(x - h)

Since the vertex = (h, k) = (0, 0),

(y-0)² = 4p(x - 0)

    y² = 4px

Since the latus rectum = 4p, the desired equation is

    y² = 12x



The blue line is the latus rectum.  Notice that it goes from (3,6) to (3,-6)

Edwin