Linear pair angles are adjacent angles that add up to 180 ° ( form a straight line)
So, by looking at the image:
12. <7 and <8 NO
Because they are not adjacent angles.
13. <2 and <4 are vertical angles . YES
Vertical angles are opposite angles
14. m<9 = m<6+m<8 YES
m<6+m<8+m<9 form a straight line, and the bisctor line makes m<9 = m<6+m<8