The square symbol on the corner of an angle represents that the angle has a measure of 90º.
Since the angle labelled as 16x-6 and the angle of 90º are alternate interior angles for the parallel lines u and v, then their measures are the same. Then:
[tex]16x-6=90[/tex]Solve for x:
[tex]\begin{gathered} \Rightarrow16x=90+6 \\ \Rightarrow16x=96 \\ \Rightarrow x=\frac{96}{16} \\ \Rightarrow x=6 \end{gathered}[/tex]Therefore, the value of x is 6.