What is the directrix (x+2)^2=-8(y-1) ?

The directrix (x+2)^2=-8(y-1) is y=3

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directrix (x+2)^2=-8(y-1)

directrix

(x + 2)^{2} = - 8 (y - 1)

y = 3

Solution steps

Rewrite

(x + 2)^{2} = - 8 (y - 1)

in the standard form:

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

(h, k) = (- 2, 1), p = - 2

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

(- 2, 1)

y-coordinate

y = 1 - p

y = 1 - (- 2)

Refine

y = 3

\frac{x ( x + 5 )}{7}

y = + x^{2} - 18 x + 73

y = x^{2} + 4 x + 3

3 x^{2} + 5 x - 4

y = - x^{2} - 1