Question 788965
You want a parabola maybe?


{{{y=a(x-h)^2+k}}} is standard form, and vertex is (h,k).


Using your given vertex, {{{y=a(x-0)^2+1}}}
{{{y=ax^2+1}}}.


Other given point on the graph is (5, -8), so put this into the equation and find a.
{{{-8=a*5^2+1}}}
{{{-9=a*25}}}
{{{a=-9/25}}}


The equation is {{{highlight(y=-(9/25)x^2+1)}}}