These are two concepts in Judaism:
עשה דוחה לא תעשה - that if there is a Mitzvah Asei in the Torah, and a Mitzvas Lo Sasei, we say that the Asei overrides the Lo Sasei, and one should do it.
For example: Attaching woolen Tzitzis to a Linen garment.
מצווה הבאה בעבירה - that if there's a Mitzvah and one does it "through" an Averiah, we say that it's not a Mitzvah, and one should not do it.
For example: Eating stolen Matzah on Pesach.
These two ideas seem similar. What makes us decide where to apply the 1st idea vs. the 2nd? What's the underlying difference?