80 points please help

Answer:
[tex]\Large \boxed{\sf \angle 6 + \angle 8}[/tex]
Step-by-step explanation:
Supplementary angles add up to 180°
Angles on a straight line add up to 180°
[tex]\angle 1 + \angle 2=180\°[/tex]
[tex]\angle 4 + \angle 8=180\°[/tex]
Interior angles add up to 180°
[tex]\angle 7 + \angle 6=180\°[/tex]
[tex]\angle 6+ \angle 8\neq 180\°[/tex]