1) 360°-18°-18°-3x°-3x°=0
6x=324°
x=54°
2) 180°-49°-(x+3)°=0
(x+3)°=131°
x=128°
3) 90°-42°-4x°=0
4x°=48°
x=12°
4) 180°-86°-2x°=0
2x°=94°
x=47°
5) 360°-117°-117°-3x°-3x°=0
6x=126°
x=21°
6) 90°-66°-8x°=0
8x=24°
x=3°
7) 180°-22°-(x-5)°=0
(x-5)°=158°
x=163°
8) 90°-2x°-2x°=0
4x°=90°
x=22.5° (i don't know if you can leave it like this or you have to write it in another way)
9) 90°-57°-3x°=0
3x°=33°
x=11°
