Question 983264
This one is easier because the process involves factoring a {{{-1}}} and the missing square term is easy to identify.  The term is 4.


{{{y=-(x^2+4x+7)}}}
{{{y=-(x^2+4x+4-4+7)}}}
{{{y=-((x+2)^2+3)}}}
{{{highlight(y=-(x+2)^2-3)}}}