blast burn can only be taught to your starter, and only if its the fire starter pokemon. You get it in blackthorn city, there's a house with 4 people in it, one of them can teach you frenzy plant, hydro cannon or blast burn depending on your starter
On island 2. There is a waterfall. Go up it and you will see a house. Go inside it and a woman will teach you blast burn if your starter Pokemon was charizard, hydro cannon if your starter Pokemon was blastoise, and frenzy plant if your starter Pokemon was venasaur.
You have to go to the Pokemon move house in Blackthorn City and go to the ultimate move tutor
game corner in golden rod for 5500 coins
no
Go to Two Island, then to Cape Brink. Go all the way up and you'll find a house. Inside is where you can get blast burn for your Charizard.
Serebii.net
You can't find Mew in Pokemon Silver.
You find Focus Blast in Wellspring Cave.
all factorys
in all glaciers
Its often on google images
there is not a secretpotion in Pokemon silver Daniel robertson