Can someone on 3 vertex, parabola questions real quick?
1. find the standard form of the equation of the parabola with a focus at (7, 0) and a directrix at x = -7.
y = 1/28x^2
x = 1/28y^2
-28y = x^2
y^2 = 14x

2. find the standard form of the equation of the parabola with a vertex at the origin and a focus at (0, -4).
y = -1/4x^2
y^2 = -4x
y^2 = -16x
y = -1/16x^2

3. find the standard form of the equation of the parabola with a focus at (0, -9) and a directrix y = 9.
y = -1/9x^2
y^2 = -36x
y = -1/36x^2
y^2 = -9x