Respuesta :

(X -5)^2 = 12(Y +4).

The standard form of a parabola  (x - h)2 = 4p (y - k), where the focus is (h, k + p). I used the given information to plug in the numbers into the standard form equation.

Answer:

[tex]x=\frac{1}{12}(y-4)^{2}-5[/tex]

Step-by-step explanation:

In this problem we have that

The vertex and the focus has the same y-coordinate, therefore, is a horizontal parabola

The equation of a horizontal parabola is of the form

[tex]x=a(y-k)^{2}+h[/tex]

where

(h,k) is the vertex

The coordinates of the focus are equal to [tex](h+\frac{1}{4a} ,k)[/tex]

we have in this problem

[tex]focus (-2,4)[/tex]

[tex]vertex (-5,4)[/tex]

substitute

[tex](h,k)=(-5,4)[/tex]

[tex](-2,4)=(-5+\frac{1}{4a} ,4)[/tex]

so

Find the value of a

[tex]-2=-5+\frac{1}{4a}\\ \\\frac{1}{4a}=3\\ \\a=\frac{1}{12}[/tex]

The equation of the horizontal parabola is equal to

[tex]x=\frac{1}{12}(y-4)^{2}-5[/tex] ------> open to the right