you bet it can
No, in fact, vertical angles can't be a linear pair. Vertical angles are opposite from each other which also make them equal each other. A linear pair has two angles adjacent to each other that eqaul 180 degrees.
In a Linear Pair the 2 angles add up to 180 degrees while Vertical Angles are just 2 vertical angles that are congruent.
no it's impossible
Yes, they can.
sometime true
vertical angles theorem
Forgotten, as requested.
Yes.
No. All linear pair angles are supplementary, but supplementary angles do not have to be a linear pair.
Yes, a vertical line is linear, but it is not a function, because every point on the line has the same x value.
All supplementary angles do not form a linear pair. The opposite angles of any quadrilateral inscribed in a circle (a cyclic quadrilateral) are supplementary but they are not a linear pair. However, all linear pair are supplementary.