plug and chug
(y-k)^2 = 4a (x-h)
k = 8 given
h = -9 given
distance from vertex to directrix = a
distance from -9 to - 16 = 7 = a (positive for directrix to the left of the vertex)
so
(y-8)^2 = 28 (x+9)
Find the standard form of the equation of the parabola with the given characteristics.
Vertex: (-9, 8); directrix: x = -16
3 answers
Focus: (1515,00); Directrix: xequals=negative 15
Focus: (15,0); Directrix: x= -15