What is the directrix y=-3(x+2)^2+5 ?

The directrix y=-3(x+2)^2+5 is y= 61/12

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directrix y=-3(x+2)^2+5

directrix

y = \frac{61}{12}

Solution steps

Rewrite

y = - 3 (x + 2)^{2} + 5

in the standard form:

4 (- \frac{1}{12}) (y - 5) = (x - (- 2))^{2}

(h, k) = (- 2, 5), p = - \frac{1}{12}

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, 5)

y-coordinate

y = 5 - p

y = 5 - (- \frac{1}{12})

Refine

y = \frac{61}{12}