Find the absolute maximum and minimum values of the function over the indicated interval, and indicate the $x-$values at which they occur.

$f(x)=x^2-4x-8$;$[1,6]$

The absolute maximum value is $,$ at $x=.$

$($Use a comma to separate answers as needed.$)$

The absolute minimum value is at $x=$

$($Use a comma to separate answers as needed.$)$