What is the directrix 7x^2-3 ?

The directrix 7x^2-3 is y=-85/28

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directrix 7x^2-3

directrix

7 x^{2} - 3

y = - \frac{85}{28}

Solution steps

Rewrite

y = 7 x^{2} - 3

in the standard form:

4 \cdot \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{85}{28}

2 y^{2} - 8 x = 0

y = \frac{1}{4} x^{2}

y = 2 x^{2} - 2

y = 4 x^{2} + 8 x - 20

2 x^{2} - 4 x + 15