Respuesta :

Answer:

x = 18.

Step-by-step explanation:

The 2 amgles are adjacent so add up to 180 degrees so we have:

x^2 - 11x + 3x = 180

x^2 - 8x - 180 = 0

(x -18)(x + 10) = 0

x = -10, 18.

x = -10 cannot be  correct because that would make the 3x angle = -30.