What is the directrix x=(-y-1)(y+3) ?

The directrix x=(-y-1)(y+3) is x= 5/4

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directrix x=(-y-1)(y+3)

directrix

x = (- y - 1) (y + 3)

x = \frac{5}{4}

Solution steps

Rewrite

x = (- y - 1) (y + 3)

in the standard form

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

(h, k) = (1, - 2), p = - \frac{1}{4}

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

- p

from the center

(1, - 2)

x-coordinate

x = 1 - p

x = 1 - (- \frac{1}{4})

Refine

x = \frac{5}{4}

y = 4 x^{2} - 8 x + 1

y = 24 x - 3 x^{2}

x = - 5 y^{2}

y = (- x - 1) (x + 3)

2 (y - 1)^{2} - 4