Answer:
x = 13
Explanation:
You want to find x when one half of the diagonal of a parallelogram is 80 and the other half is 6x+2.
Diagonals
The diagonals of a parallelogram bisect each other, so point Y is the midpoint of each. That means ...
VY = YX
80 = 6x +2 . . . . . substitute the given values
78 = 6x . . . . . . . subtract 2
13 = x . . . . . . . . divide by 6
The value of x is 13.