Question 1159533
vertex is at  (0,2) and graph is concave upward.


{{{(x-0)^2+(y-4)^2=(x-x)^2+(y-0)^2}}}, if used from Distance Formula for definition of parabola, or the problem description


{{{x^2+(y-4)^2=y^2}}}

{{{x^2+y^2-8y+16=y^2}}}

{{{x^2-8y+16=0}}}

{{{-8y+16=-x^2}}}

{{{8y-16=x^2}}}

{{{highlight(8(y-2)=x^2)}}}, or other form if you need


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