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The focus of a parabola is (4,7) and the directrix is y=8.

What is an equation of the parabola?

A: (x−4)^2=−(y−9)

B: (x−4)^2=−4(y−9)

C: (x−4)^2=−2(y−7.5)

D: (x−4)^2=−0.5(y−7.5)

Kakarot_15  May 2, 2017
edited by Kakarot_15  May 2, 2017
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p  = - 1/2......so   the equation is

 

4p(y-7.5)   = (x - 4)^2

 

-2(y - 7.5)  = (x - 4)^2    .........."C"   is correct

 

 

 

cool cool cool

CPhill  May 2, 2017

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