The focus of a parabola is (3,−7) and the directrix is y=−4.
What is an equation of the parabola?
(A) - (x−3)2=−3(y+10)
(B) - (x−3)2=−1.5(y+5.5)
(C) - (x−3)2=−6(y+5.5)
(D) - (x−3)2=−12(y+10)
The vertex is ( 3, -5.5) = (h, k)
And p = -1.5
And we have this form
4p(y - k) = (x - h)^2
So.....the equation becomes
4(-1.5)(y - -5.5) = (x - 3)^2
-6 (y + 5.5) = ( x - 3)^2 "C" is correct
See the graph, here : https://www.desmos.com/calculator/rgyxi4lf5n
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