Resposta:
[tex]a)\\ \\ x+110^{\circ}+x=180^{\circ}\\ \\ 2x=180-110\\ \\ 2x=70\\ \\ x=70:2\\ \\ \boxed{x=35^{\circ}}[/tex]
[tex]b)\\ \\ 2x+40^{\circ}+5x-10^{\circ}+x+50^{\circ}=360^{\circ}\\ \\ 8x+80=360\\ \\ 8x=360-80\\ \\ 8x=280\\ \\ x=280:8\\ \\\boxed{ x=35^{\circ}}[/tex]
[tex]c)\\ \\ x+x+90^{\circ}=3600^{\circ}\\ \\ 2x=360-90\\ \\ 2x=270\\ \\ x=270:2\\ \\ \boxed{x=135^{\circ}}[/tex]