Answer: choice B
y = (-1/16)(x-7)^2 + 2
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Step-by-step explanation:
p = distance from vertex to focus = focal distance = 4
y = a(x-h)^2 + k is the vertex form of a parabola
(h,k) is the vertex, so (h,k) = (7,2) means h = 7 and k = 2.
'a' determines the direction the parabola faces and how stretched/compressed the graph is.
In terms of p, a = -1/(4p). The value of 'a' is negative since the vertex is above the focus. So, a = -1/(4p) = -1/(4*4) = -1/16.
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with a = -1/16, h = 7 and k = 2, we can say
y = a(x-h)^2 + k
y = (-1/16)(x-7)^2 + 2