Answer:
x = 16
Step-by-step explanation:
The 3 exterior angles of a triangle sum to 360°
sum the exterior angles and equate to 360
5x + 12 +10x - 37 + 9x + 1 = 360 , that is
24x - 24 = 360 ( add 24 to both sides )
24x = 384 ( divide both sides by 24 )
x = 16
