Find the standard form of the equation of the parabola with a focus at (-7, 0) and a directrix at x = 7.

a) x = negative 1 divided by 28y^2

b) - 28y = x^2

c) y^2 = - 14x

d) y = negative 1 divided by 28x^2

y^2 = - 28x.

Step-by-step explanation:

The general form for this type of parabola is y^2 = 4ax where the focus is at (a, 0) and the directrix is x = - a.

So substituting we get

y^2 = 4 * - 7 * x

y^2 = - 28x

x = 1 / (4p) * y^2

x = 1 / (4*-7) * y^2

x = - 1/28*y^2