Respuesta :

vialia

Answer:

x = 5

Step-by-step explanation:

39° + 90° + (7x + 16)° = 180°

39 + 90 = 129

180 - 129 = 51

7x + 16 = 51

7x + 16 - 16 = 51 - 16

7x = 35

7x/7 = 35/7

x = 5