∵ AD//BC, AF⊥BC is at point F.
∴∠ADG=∠CBG ①
∠BAE =∠AFB-∠ABF =∠AFB-∠ABC = 90-75 = 15②
AF⊥AD
So AG is the center line of the hypotenuse DE of the right triangle ADE.
∴AG= 1/2DE=GD=GE=AB
Then ∠ Dag =∠ADG, ∠AGB=∠ABG.
Let ∠ADG=X
Then ∠DAG=∠GDA=X,
∠ AGB =∠ ABG =∠ ABC-∠ CBG =∠ ABC-∠ ADG = 75-x [derived from ① ∠ADG=∠CBG] ③.
And ∠AGB is the outer corner of the triangle ADG.
Therefore, ∠AGB =∠ Dag +∠ADG=X+X=2X ④.
75-x = 2x from ③ ④
∴X=25
So ∠ abg = ∠ ABC-∠ cbg = 75-x = 75-25 = 50 ⑤.
∴ AED =∠ BAE +∠ ABG = 15+50 = 65 from ② ⑤.