Dratini can be found in Dragon's Den, level it up and evolve it.
You can't find Mew in Pokémon Silver.
It evolves at lvl 55
Level 55
Level 55 into Dragonite.
You can't get it in the silver version only heart gold
level 30 into dragonair, then level 55 into dragonite.
You have a tiny chance to find one in Dragon's Lair.
the only way is gameshark 4598F499 A44B5063 DRAGONAIR
You'll need to fish at Dragon's Den. Not with a Old Rod though, unless you want a lot of Magikarp.
You can't find Mew in Pokémon Silver.
to my knowledge,you cannot catch a dragonair in yellow version, but you can catch dratini in the safari zone
Into Dragonite (level 55)
Yes you can
55
It evolves at lvl 55
Dragonair are found rarely at Mt. Coronet.
You can only find Ledyba in Pokemon Silver and Soul Silver version.