NBA LIVE 07 BOOSTING 

This may be easier than you think as there is hardly anyone online, so it is quite easy to find a friend, if you search at the same time. 

Play and finish a Ranked Match  - 50 points

Play and finish a normal ranked match against any opponent.

No need to win, but you do need to FINISH a ranked match on Xbox Live to unlock this achievement. 

Challenge an online user/Ranked  - 100 points

Challenge an online user to a Ranked game and finish this game.

You need to challenge another player on Xbox Live to a ranked match. You must be the one to initiate the challenge. To do this, join a lobby and highlight who you want to play and then challenge them to a Ranked match. You don’t have to win, but you do need to finish the game. 

Online Multiplayer Co-op  - 100 points

Finish a multiplayer Co-op online game with at least one friend against two or more users.

You can just stick in a second controller and play against two others online, or have your friend stick in two controllers and the achievement will still unlock. However you must finish the game.

CHECK OUR ACHIEVEMENT GUIDE HERE