Answer: B) y = (1/28)x^2
Step-by-step explanation:
p = focal distance = 7
the focal distance is from the vertex to the focus
The parabola opens upward (since the vertex is below the focus) so 'a' is positive and a = 1/(4p) = 1/(4*7) = 1/28
The vertex is (h,k) = (0,0)
Put this all together into the formula below and simplify
y = a(x-h)^2 + k
y = (1/28)(x - 0)^2 + 0
y = (1/28)x^2