Respuesta :

ganjilaya2019

Answer:

x = 19

Step-by-step explanation:

(5x + 4)° + (x - 2)° + (3x + 7)° = 180°

(5x + x + 3x)° + (4 - 2 + 7)° = 180°

9x° + 9° = 180° → ÷9

x + 1 = 20

x = 20 - 1

x = 19