Please tell me if it is safe to mix adderall (dextroamphetamine and racemic amphetamine) and alcohol?

I wouldn't: This is not advisable.

End of the day, OK: Not really a great idea, unless it's an extended release variety at the end of a work day. After 6 or 7 hours, it's been nearly entirely metabolized. At that point if you want to grab a beer after work, knock yourself out. Earlier than that and your throwing a CNS depressant in with a cortical stimulant. Never a good combo.

Timing and amount: Alcohol is sedating, and Adderall (dextroamphetamine and racemic amphetamine) has opposite effect. Taking Adderall (dextroamphetamine and racemic amphetamine) in the morning and drinking a beer or glass of wine in the evening should not be a problem unless one glass leads to many glasses and alcohol abuse. Definitely a problem to take Adderall (dextroamphetamine and racemic amphetamine) and drink alcohol at the same time of day.