Step-by-step explanation:
in a parallelogram, opposite angles are equal..
so C is 4a + 22. and B is 6a - 12.
sum of interior angles in a quadrilateral = 360
4a + 22. + 6a - 12. + 4a + 22. + 6a - 12 = 360
20a + 20 = 360
20a = 340
a = 17
sum of angles on a straight line = 180
B + x = 180
6 ( 17) - 12 + x = 180
102 + × = 180
× = 180 - 102
× = 78
