Answer:
See Below.
Explanation:
We are given that PQRS is a parallelogram, where X and Y are points on the diagonal QS such that SX = QY.
And we want to prove that quadrilateral PXRY is a parallelogram.
Since PQRS is a parallelogram, its diagonals bisect each other. Let the center point be K. In other words:

SK is the sum of SX and XK. Likewise, QK is the sum of QY and YK:

Since SK = QK:

And since we are given that SX = QY:

So we now have:

Since XY bisects RP and RP bisects XY, PXRY is a parallelogram.