Respuesta :

Answer: 140°

Step-by-step explanation:

x = 11

5 x 11 = 55

55 - 15 = 40

The 5x-15 = 40°

tHe 3x+7 is opposite, so it also equals 40°

40 + 40 = 80°

360° - 80° = 280

280 divided by 2 = 140°