1. External angle:
[tex] 9x-5=\dfrac{1}{2}(158-64)\\\\\\9x-5=\dfrac{1}{2}\cdot94\\\\\\9x-5=47\\\\9x=47+5\\\\9x=52\qquad|:9\\\\\\\boxed{x=5\frac{7}{9}} [/tex]
2. Internal angle:
[tex] 5x-6=\dfrac{1}{2}(101+37)\\\\\\5x-6=\dfrac{1}{2}\cdot138\\\\\\5x-6=69\\\\5x=69+6\\\\5x=75\qquad|:5\\\\\boxed{x=15} [/tex]
