what is the meaning of the "axiom of the linear pair"
We know that, axioms are the basic assumptions which are accepted without any demonstration.
So, axiom of linear pair suggests that if a straight line is cut by another vertical line then the sum of the angles formed by the vertical line on the given line is always equal to 180° and it is universally true.
For example, in the given figure, line AB is cut by the line OC.
Therefore, ∠AOC + ∠BOC = 180°
Hope you get it!!