Answer:
x = 6
Step-by-step explanation:
According to Exterior Angle Property of a triangle , measure of an exterior angle is the sum of its opposite interior angles.
Using the exterior angle property ,
[tex]17x - 23 = 3x + 17 + 8x - 4[/tex]
[tex] = > 17x - 23 = 11x + 13[/tex]
[tex] = > 17x - 13x = 23 + 13[/tex]
[tex] = > 6x = 36[/tex]
[tex] = > x = \frac{36}{6} = 6[/tex]
