What is the directrix y=(x+4)^2 ?

The directrix y=(x+4)^2 is y=-1/4

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directrix y=(x+4)^2

directrix

y = (x + 4)^{2}

y = - \frac{1}{4}

Solution steps

Rewrite

y = (x + 4)^{2}

in the standard form:

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

(h, k) = (- 4, 0), p = \frac{1}{4}

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

(- 4, 0)

y-coordinate

y = 0 - p

y = 0 - \frac{1}{4}

Refine

y = - \frac{1}{4}

y = x^{2} + 2 x - 1 - (2 x^{2} - 3 x + 6)

y = 2250 (0.015 - 0.001 x)^{2} + 6000 x

2 x^{2}

y = 12 x^{2} - 72 x + 77

4 - x - x^{2}