It's given that WXYZ is a parallelogram. In a parallelogram, the adjacent angles sum up to 180°. Here, 2u - 2 & 3u + 12 together make 180° because they are adjacent angles.
2u - 2 + 3u + 12 = 180
2u + 3u - 2 + 12 = 180
5u + 10 = 180
5u = 170
u = 170/5
u = 34
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