Respuesta :

ANSWER

[tex]x = - 6[/tex]

EXPLANATION

The given parabola has equation:

[tex] {(y - 3)}^{2} = 20 {(x + 1)}^{2} [/tex]

This parabola opens in the direction of the positive x-axis.

This can be rewritten as:

[tex]{(y - 3)}^{2} = 4(5) {(x + 1)}^{2} [/tex]

The vertex is (-1,3)

The directrix of this parabola is

[tex]x = - 1 - 5[/tex]

[tex]x = - 6[/tex]

Answer:

The equation of the directrix of the parabola is x=-6.

Step-by-step explanation:

The given equation is

[tex](y-3)^2=20(x+1)[/tex]            .... (1)

If a parabola is defined as

[tex](y-k)^2=4p(x-h)[/tex]              .... (2)

Where, (h,k) is vertex and the directix of the parabola is x=h-p.

From (1) and (2), we get

[tex]h=-1,k=3[/tex]

[tex]4p=20[/tex]

[tex]p=5[/tex]

The value of p is 5.

The equation of directix is

[tex]x=h-p[/tex]

[tex]x=-1-5[/tex]

[tex]x=-6[/tex]

Therefore the equation of the directrix of the parabola is x=-6.