Give the standard form of the equation of the parabola with the given characteristics. vertex: (-7,-9)directrix: $x = - 9$
A) $( x - 7 ) ^ { 2 } = - 8 ( y - 9 )$
B) $( y - 9 ) ^ { 2 } = - 8 ( x - 7 )$
C) $( y + 9 ) ^ { 2 } = 8 ( x + 7 )$
D) $( y - 9 ) ^ { 2 } = 8 ( x - 7 )$
E) $( x + 7 ) ^ { 2 } = - 8 ( y + 9 )$

Question

Quizplus · Accepted Answer

The parabola opens horizontally because the directrix is vertical. The vertex form for a horizontal parabola is $(y - k)^2 = 4p(x - h)$. The vertex is $(-7, -9)$ and the directrix is $x = -9$, so $p = 2$. Thus, the equation is $(y + 9)^2 = 8(x + 7)$.

Give the Standard Form of the Equation of the Parabola x=−9x = - 9x=−9

Give the Standard Form of the Equation of the Parabola $x = - 9$