x = 20 is the answer.
Step-by-step explanation:
When a parallel lines cut by a transversal, then the alternate exterior angles are congruent.
So the given 2 angles add up to 180 degrees.
5x+ 9 + 3x+ 11 = 180
8x + 20 = 180
8x = 180 - 20 = 160
x = 160/8 = 20
