Nomor 6 caranya gimana? Bantu ya

2x + 120° = 180° (sudut berpelurus)
2x = 180-120
2x = 60
x = 60/2
x = 30°

120° + 2x = 180°
2x = 180 - 120
2x = 60
x = 60 / 2
x = 30°
semoga membantu..