Answer:
directrix
Explanation:
the equation of a vertically opening parabola in vertex form is
y = a(x - h)² + k
where (h, k ) are the coordinates of the vertex and a is a multiplier
y = 5(x - 3)² + 4 ← is in vertex form
with a = 5, h = 3 , k = 4
the equation in this form has
focus (h, k +
) and directrix is y = k -

using the above values , that is k = 4 and a = 5 , then
y = 4 -
← is the equation of the directrix