Answer:
x = 20 degrees, angle ABC = 98 degrees
Explanation:
The two inner angles sum up to 180 degrees. This is a general rule when you have two parallel lines and another line intersecting through both lines.
So angles ABC and DCB sum up to 180.
4x + 18 + 2x + 42 = 180
6x + 60 = 180
6x = 120
x = 20 degrees
Plugging this back in angle ABC,
4(20) + 18 = 98 degrees