Please draw a picture first (see attached).
If E is the center of the parallelogram, then it is also the midpoint of diagonals AC and BD, that is, AE = EC and DE = EB.
Substituting the given values,
3x = y
4x = y + 1
We have a system of equations so we can solve for x and y.
4x = (3x) + 1
x = 1
3x = y
3(1) = y
y = 3
Please comment with any questions!