Respuesta :

Answer:

71°

Step-by-step explanation:

3x° + (x - 11)° + (2x - 55)° = 360°

3x + x - 11 + 2x - 55 = 360°

6x - 66 = 360°

6x = 360° + 66°

6x = 426°

x = 71°