What is the directrix y=-7x^2-3 ?

The directrix y=-7x^2-3 is y=-83/28

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

directrix y=-7x^2-3

directrix

y = - 7 x^{2} - 3

y = - \frac{83}{28}

Solution steps

Rewrite

y = - 7 x^{2} - 3

in the standard form:

4 (- \frac{1}{28}) (y - (- 3)) = (x - 0)^{2}

(h, k) = (0, - 3), p = - \frac{1}{28}

Parabola is symmetric around the y-axis and so the directrix is a line parallel to the x-axis, a distance

- p

from the center

(0, - 3)

y-coordinate

y = - 3 - p

y = - 3 - (- \frac{1}{28})

Refine

y = - \frac{83}{28}

x^{2} - 10

y^{2} + 36 x = 0

(y - 3)^{2} = - 2 (x + 2)

y = (x + 314)^{2}

y = x^{2} - 13 x + 40