Question 1106108
How do you mean "equation"?


Here is a possibility.
{{{y=a(x-2)^2-2}}}
{{{y+2=a(x-2)^2}}}
{{{a=(y+2)/(x-2)^2}}}
{{{a=(0+2)/(4-2)^2}}}
{{{a=2/(2^2)}}}
{{{a=1/2}}}


{{{highlight(y=(1/2)(x-2)^2-2)}}}, but not the only possible answer