SOLUTION: How can you tell if a parabola opens left/right or up/down such as for this question. The foucs (-3,5) diretrix at x= 1 --> write it in standard form and tell whether it opens r

Question 23721: How can you tell if a parabola opens left/right or up/down such as for this question.
The foucs (-3,5) diretrix at x= 1 --> write it in standard form and tell whether it opens right/left or up/dpwn.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Draw the picture of the focus and the directrix on
a coordinate system. Notice the focus is "4" to the
left of the directrix. So the parabola opens to the
left. The vertex is half way between the focus and
the directrix so the vertex is at (-1,5)
The standard form for your parabola is as follows:
(y-k)^2 = 4p(x-h)
h=-1, k=5,
p is the distance from the vertex to the focus = -2
The equation is (y-5)^2 = -8(x+1)
I think I am defining "p" correctly but you might check
it out in your textbook.
Cheers,
stan H.
RELATED QUESTIONS
How can you tell if a parabola opens up or down from the formula... (answered by solver91311)

Determine if the following parabola opens up, down, left or right.... (answered by addingup)

For f(x)=ax^2+bx+c, how can we tell if the parabola open up or opens... (answered by jsmallt9)

Name the vertex and axis of symmetry for each quadratic function. Tell wherther the... (answered by RAY100)

Name the vertex and axis of symmetry for each quadratic function. Tell wherther the... (answered by Mathtut)

Name the vertex and axis of symmetry for each quadratic function. Tell wherther the... (answered by RAY100,stanbon)

explain how you can tell whether a parabola opens upward, downward, to the left, or to... (answered by stanbon)

If you know that the vertex of a quadratic is at (3, 16) and one of the zeros is at (-1,... (answered by josgarithmetic)