You say "finally my question is here", but I see know question!
You say "I am able to imagine on the number line in my mind". What do you mean by that? If x= 2 then , a point on the number line, but for general x, can be any point representing a non-negative number.
As for , if x= 4 then but, for any non-negative x, can, again, be any point representing a non-negative number.