Question 914011
It seems to open down.  POINT (not Parabola) on the parabola is (2,-1).


{{{y=a(x-0)^2+1}}}, using standard form and the given vertex.  You want to use the other known point to find the value for the factor a.


{{{y=ax^2+1}}}
{{{y-1=ax^2}}}
{{{a=(y-1)/x^2}}}


Do the rest.