what is the difference between land contract and article of agreement?

Answer 1

It depends on the context, and whether you are talking about specific documents with those names, or the concepts.

Generally, a "land contract" follows all the rules (as per the country/state/province you are in) for a contract.

"Articles of agreeement" are usually less formal, and set forth the intent of the parties without actually being a contract.

Answer 2

When it comes down to it, not a thing. They're just different terms that refer to a bargain for exchange.