(1)∠ABC=∠ABD+∠DBC=30°+45°=75°
(2)∠ADC=90°+45°=135°
DE平分∠ADC,
∠EDC=135°÷2=67.5°,
∠EDB=∠EDC-∠BDC=67.5°-,45°=22.5°,