Answer:
8
Explanation:
when parallel lines are intersected by another line they all have the same intersection angles with this additional line. they have to have that, because a parallel line mimics any other parallel line with every attribute except for the actual physical position.
and the angles on one side of an intersected line are the same as on the other side, they are just left-right mirrored.
therefore,
8x - 4 = 60
8x = 64
x = 8