Answer the following questions for the function
f(x)=xx2+4\displaystyle {f{{\left({x}\right)}}}={x}\sqrt{{{x}^{{2}}+{4}}}
defined on the interval 7x4\displaystyle -{7}\le{x}\le{4}.

f(x)\displaystyle {f{{\left({x}\right)}}} is concave down on the interval x =   to x =  

f(x)\displaystyle {f{{\left({x}\right)}}} is concave up on the interval x =   to x =  

The inflection point for this function is at x =  

The minimum for this function occurs at x =  

The maximum for this function occurs at x =