Find an equation for the parabola described.
-Vertex at (3, -4); focus at (3, -6)
A) $( x - 3 ) ^ { 2 } = 8 ( y + 4 )$
B) $( x - 3 ) ^ { 2 } = - 8 ( y + 4 )$
C) $( y - 4 ) ^ { 2 } = - 12 ( x + 3 )$
D) $( y - 4 ) ^ { 2 } = 12 ( x + 3 )$

Question

Find an equation for the parabola described.
-Vertex at (3, -4); focus at (3, -6) 
A) $( x - 3 ) ^ { 2 } = 8 ( y + 4 )$
B) $( x - 3 ) ^ { 2 } = - 8 ( y + 4 )$
C) $( y - 4 ) ^ { 2 } = - 12 ( x + 3 )$
D) $( y - 4 ) ^ { 2 } = 12 ( x + 3 )$

Quizplus · Accepted Answer

The focus and vertex indicate a vertical parabola opening downwards. The distance between the vertex and focus is 2, so $4p = -8$, where $p$ is the distance from the vertex to the focus. Thus, the correct equation is $(x - 3)^2 = -8(y + 4)$.

Find an Equation for the Parabola Described (x−3)2=8(y+4)( x - 3 ) ^ { 2 } = 8 ( y + 4 )(x−3)2=8(y+4)

Find an Equation for the Parabola Described $( x - 3 ) ^ { 2 } = 8 ( y + 4 )$