Number Theory | Lemma 1 for Fundamental Theorem of Arithmetic

We prove a lemma in preparation to prove the Fundamental Theorem of Arithmetic.

[PunmasterSTP]

Another phenomenal video; lemma look at a couple more...

[georgesadler]

Professor Penn, thank you for a powerful proof of Lemma 1 for The Fundamental Theorem of Arithmetic..

[Hellomyfeet]

I do not understand why for integers x, y there exists ax+py=1, if you could explain it I'd be grateful.