m∠X = 105°
BCDE is a parallelogram and BE = 11.
The diagonals of a parallelogram bisect each other.
Since the diagonals bisect each other, BF = FE and DF = FC. BE is a diagonal, and BE = 11. The other diagonal is DB, and it is bisected by diagonal BE, so BF+FE = BE or 2 * BF = BE, where BF = 11/2 and DB = 2 * BF. Therefore, DB=11.
DB = 11