tolong di jaeab y'ya soalnyaesok dikumpulin

5x + 80° = 180°
5x = 180° - 80°
5x = 100°
x = 100/5
x = 20°

semoga membantu!
Maaf tadi salah

5x dan 80° bersebrangan

5x + 80 = 180
5x = 180 - 80
5x = 100
x = 20°