Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Items to consider:
1.0 Want some Ap, lifesteal and an excellent item for Jax: Hextech Gunblade
2.0 Facing against another Jax: Sword of Divine + Banshee's Veil
3.0 You got no tank:
3.1 Option 1 Enemy team have dpsers: Warmogs + Tornmail
3.2 Option 2 Enemy team have so much ap: Force of nature + Banshee's Veil
4.0 The enemy team is stacking magic resist: Malady
5.0 Facing against loads of hp hero's like Cho'Gat: Madred's Bloodrazor
6.0 Facing against Dr.Mundo
6.1 If your teamates got Ignite: Tell them to Ignite Mundo's Ult.
6.2 Without ignite: Executtioner's Calling (Use the active against Mundo's Ult.)
7.0 The match isn't going well: Play defensive and get one Avarice Blade or Kage's Lucky pick (Passive helps a lot because Jax items are expensive.)
8.0 Facing Against Armored teams: Get Black Cleaver + Last Whisper.
9.0 Facing against Casters: Get Wit's End.
There is my way to play Jax on 3v3, please try it before comment and rate. Im still trying out some items.
I accept suggestions, will try them and if they work I'll put the names of those who helped in a separate section.
Thanks for reading.