Respuesta :

Step-by-step explanation:

x + 1 + 2x + 2 + 12x - 18 = 180 (sum angles in triangle)

15x - 15 = 180

15x = 195

x = 13deg

Topic: Angles

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Step-by-step explanation:

(x+1)°+(2x+2)°+(12x-18)°=180°

15x+3°-18°=180°

15x+15°=180°

15x=180°-15°

x=165°/15°

x=11° Answer..