What is the directrix (x-3)(x-7) ?

The directrix (x-3)(x-7) is y=-17/4

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directrix (x-3)(x-7)

directrix

(x - 3) (x - 7)

y = - \frac{17}{4}

Solution steps

Rewrite

y = (x - 3) (x - 7)

in the standard form

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

(h, k) = (5, - 4), 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

(5, - 4)

y-coordinate

y = - 4 - p

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

Refine

y = - \frac{17}{4}

- (x - 1)^{2} + 5

1.5 + 17.67 t - 4.905 t^{2}

x^{2} = 32 y

y = (x + 6) (x - 2)

6 x^{2} + 7 x - 3