This is a parallelogram. What we know about the diagonals is that they intersect each other at their midpoints. In other words, QT = ST, and PT = RT. So that gives us 2 equations:
If QT = ST, then
2x = y + 3
If PT = RT, then
x + 5 = y Solving by substitution, plug x + 5 in for y in the first equation.
