I think that she started with 10.. I'm not 100% sure, though
B should be correct
Hope that helped
I used a graphing calculator for this.
The solution my calculator got was:
(-2.625, 0.688) My calculator is very accurate, I don't think the test expects it to be like that.
Let's find the closest coordinates.
"B" is the closest.
I hope this helps!
~kaikers
Refer to the diagram shown below.
The distance, d, from the focus to a point P (x,y) is equal to the distance from the directrix to P.
Therefore
d² = (6 - y)²
= (x + 2)² + y²
That is,
36 - 12y + y² = (x + 2)² + y²
12y = -(x + 2)² + 36
The equation of the parabola is
y = -(1/12)(x + 2)² + 3
It may be written as
-12(y - 3) = (x + 2)²
The leading coefficient -1/12 is negative, therefore the curve opens downward.
Answer:
The equation is (x + 2)² = -12(y - 3).
The curve opens downward.