Answer:
35
Explanation:
the given two unknown angles are co-interior angles and for the lines to be parallel, they must be equal . So on equating them , we have ,
5x - 54 = 3x + 16
5x - 3x = 54 + 16
2x = 70
x = 70/2 = 35 [ required answer]
and we are done!
-Rishabh