Explanation:
given the rules of intersecting lines, the angles are the same in both sides of such a line (only left-right mirrored).
so,
z = 112°
and the sum of all angles around a point on one side of an line is also always 180°.
180 = 112 + 6x - 22 = 90 + 6x
6x = 90
x = 90/6 = 15