A linear pair of angles is a pair of adjacent angles formed when two lines intersect each other. Adjacent angles are formed when two angles have a common vertex and a common arm but do not overlap. Example below:
In the image above,
In figure 1 of the problem .
Vertical angles are pair angles formed when two lines intersect. They are opposite to each other at the vertex. It is like an angle formed by a scissor by the handle and its blade.
In the image above,
In figure 1