Question 912827
Convert to vertex form,
{{{f(x)=-2(x^2+(13/2)x)+16}}}
{{{f(x)=-2(x^2+(13/2)x+(13/4)^2)+16+2(13/4)^2}}}
{{{f(x)=-2(x+(13/4))^2+256/16+338/16}}}
{{{f(x)=-2(x+(13/4))^2+594/16}}}
{{{f(x)=-2(x+(13/4))^2+297/8}}}
Since {{{-2<0}}}, the parabola opens downwards and the value at the vertex is the maximum value.
Domain : ({{{-infinity}}},{{{infinity}}})
Range : ({{{-infinity}}},{{{297/8}}}]