SOLUTION: y^2=21x-7 Whats the focus and directrix?

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Question 963403: y^2=21x-7
Whats the focus and directrix?
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
y^2=21x-7
Whats the focus and directrix?
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This is an equation of a parabola that opens rightward.
Its basic equation:(y-k)^2=4p(x-h)
For given equation: y^2=21(x-1/3)
vertex: (1/3, 0)
axis of symmetry: y=0 or x-axis
4p=21
p=21/4
focus:(33/4,0) (p-distance right of vertex on the axis of symmetry)
directrix:(29/6,0) (p-distance left of vertex on the axis of symmetry)