Respuesta :

sqdancefan

Answer:

  x = -8

Step-by-step explanation:

The sum of arcs of a semicircle is 180°. That means the arc whose measure is -11x+12 has a measure of 180° -80° = 100°.

  -11x +12 = 100

  -11x = 88 . . . . . . subtract 12

  x = -8 . . . . . . . divide by -11