Ka, tolong dijawab pakai caranya yaaa, besok dikumpulkan...

(3x+3)° + (5x+7)° + (2x-6)° = 180°
10x = 180°- 4°
10x = 176°
x = 17,6°

ditanya
sudut EBC = (5x + 7)° + (2x - 6)°
= (5(17,5) + 7)° + (2(17,5) - 6)°
= (87,5 + 7)° + (35 - 6)°
= 94,5° + 29°
= 123,5°

jadi jawabannya C