Question 840671
If the vertex is at the Origin write the equation of the parabola and identify the directrix
4. Focus at (0, 1)
parabola opens upward:
axis of symmetry:x=0 or y-axis
basic form of equation: x^2=4py
p=1(distance from vertex to given focus on the axis of symmetry)
4p=4
equation; x^2=4y
directrix: y=-1(p-distance from vertex to directrix on the axis of symmetry)
..
5. Focus at (0, 5)
parabola opens upward:
axis of symmetry:x=0 or y-axis
basic form of equation: x^2=4py
p=5(distance from vertex to given focus on the axis of symmetry)
4p=20
equation; x^2=20y
directrix: y=-5(p-distance from vertex to directrix on the axis of symmetry)
..
6. directrix y = 7
parabola opens downward:
axis of symmetry:x=0 or y-axis
basic form of equation: x^2=-4py
p=7(distance from vertex to given directrix on the axis of symmetry)
4p=28
equation; x^2=-28y
focus: y=(0,-7)(p-distance from vertex to focus on the axis of symmetry)
..
7. directrix y = -3 
parabola opens upward:
axis of symmetry:x=0 or y-axis
basic form of equation: x^2=4py
p=3(distance from vertex to given directrix on the axis of symmetry)
4p=12
equation; x^2=12y
focus: y=(0,-3)(p-distance from vertex to focus on the axis of symmetry)