What is the value and is it minimum or max

Answer:
minimum and value of 4
Step-by-step explanation:
[tex]\frac{dx}{dy} = 2x-8[/tex]
When [tex]\frac{dx}{dy}=0[/tex] we will be able to get the critical points.
[tex]2x-8 =0[/tex][tex]x=4[/tex]
The graph is a quadratic graph with a 'U' shape, thus it has a minimum critical point.