What is the directrix-2x^2-4x+y+70=0 ?

The directrix-2x^2-4x+y+70=0 is y=-577/8

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directrix-2x^2-4x+y+70=0

directrix

- 2 x^{2} - 4 x + y + 70 = 0

y = - \frac{577}{8}

Solution steps

Rewrite

- 2 x^{2} - 4 x + y + 70 = 0

in the standard form

4 \cdot \frac{1}{8} (y - (- 72)) = (x - (- 1))^{2}

(h, k) = (- 1, - 72), p = \frac{1}{8}

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

(- 1, - 72)

y-coordinate

y = - 72 - p

y = - 72 - \frac{1}{8}

Refine

y = - \frac{577}{8}

19 - t^{2}

x^{2} - 4 x + 8 y - 4 = 0

4 t^{2}

3 x^{2} - 2

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