tolong jawab pertanyaan

180 - 150
= 30°

180 - (30 + 90)
= 180 - 120
= 60°

60 + (7x - 6) = 180°
60 + 7x - 6 = 180
54 + 7x = 180
7x = 180 - 54
7x = 126
x = 126/7
x = 18°