This question keeps getting asked, use the search engine.
Amphetamines and benzodiazepines aren't particularly dangerous to combine. They don't actually cancel each other out, but the benzos will make you unable to "feel" the amphetamines is you dose too much.
But taking your normal recreational dose of both of those drugs at the same time wouldn't make either of them more dangerous, no...
In fact, benzos are often the first thing they give you for an amphetamine overdose, because panic and anxiety can greatly enhance the CNS stimulation of amphetamines to a dangerous level.
Edit: In fact, the OP started an almost identical thread about xanax and adderall. Please refrain from starting threads about the exact same thing!