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Answer:
- (d) y = -1/24x²
- (b) y = 1/36x²
Step-by-step explanation:
1. The point halfway between the focus and directrix is the origin. That is, the vertex of the parabola is the origin. Then its equation can be written ...
y = 1/(4p)x²
where p is the distance from the vertex (origin) to the focus. Here, that distance is -6, so 4p = -24 and the parabola's equation is ...
y = -1/24x²
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2. Same deal. The vertex is the origin, but this time the focus is above the origin by 9 units. Then the equation is ...
y = 1/36x²
