the sum of the internal angles of a triangle is 180, therefore:
[tex]\begin{gathered} 45+64+y=180 \\ \text{solving for y:} \\ y=180-45-64=71 \\ y=71 \\ y\text{ and x are supplementary, so:} \\ x+y=180 \\ \text{Solving for x:} \\ x=180-71 \\ x=109 \end{gathered}[/tex]
