What value of x would make the figure a parallelogram (show your math please)

Answer:
2
Step-by-step explanation:
Diagonals of a parallelogram bisects each other.
Therefore,
4x = 8
x = 8/4
x = 2
Or
5x = 3x + 4
5x - 3x = 4
2x = 4
x = 4/2
x = 2