To solve this problem we have to remember that diagonals of a parallelogram bisect each other. This means that they intersect in the midle point of each other. From this we can conclude that
[tex]\begin{gathered} x-3=15 \\ \text{and} \\ y+3=12 \end{gathered}[/tex]Once we have our equations we can solve them. Let's find x
[tex]\begin{gathered} x-3=15 \\ x=15+3 \\ x=18 \end{gathered}[/tex]Now, let's find y
[tex]\begin{gathered} y+3=12 \\ y=12-3 \\ y=9 \end{gathered}[/tex]Then x=18 and y=9,
