Suppose that $f(x,y)=x^2-xy+y^2-5x+5y$ with $D=\{(x,y)|0yx5\}.$

The critical point $off(x,y)$ restricted $to$ the boundary $ofD,$ not $at$ a corner point, $isat$

$(a,b).$ Then $a=$

and $b=$

Absolute minimum $off(x,y)is$

and $absolute$ maximum $is$