YXW + YXZ = 180
So
x + 28 + 3x + 2 = 180
4x + 30 = 180
4x = 150
x = 150 / 4 = 75 / 2 = 37.5°
WXZ is a straight angle, which 180 degrees. Our equation is YXW + YXZ = 180 degrees. In other words; x + 28 + 3x + 2 = 180 degrees. So we simplidy and get 4x = 150. 150 / 4 is 37.5, so x = 37.5