∠1 and ∠2 are alternate exterior angles where transversal BE crosses parallel lines AC and DF, therefore they are equal. ∠2 and ∠3 are opposite angles of a parallelogram, therefore they are equal.
... ∠1 = ∠2
... 3x -5 = 2x +15 . . . . substitute the given values
... x = 20 . . . . . . . . . . . add 5-2x
The measures of angles 1, 2, and 3 are 2·20+15 = 55 . . . degrees.
