geometry

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