That is not a copmmon term in Oklahoma but as others have said there is not real contract unless in writing and agreed to by all parties as I understand it.

An Express contract is in writing, while we hear more issues with Implied contracts.

Implied contracts are common when agents work with buyers without taking the time to get a Buyers agency signed and start advising and talking like they are representing the buyer.

The buyer thinks they have an agent while the agent is really contractually obligated to serve the needs of the Seller.

Please dont take this as legal advice though since I am not a lawyer, seek a lawyer for real advice on contracts, and your instructor may have some insight on this too.

All signed contracts in writing are express rather than implied contracts.

 Good luck with your studies.

Express = written vs. implied, which is not a Contract in either of my states (NC or SC).

The problems tend to lie in "Implied contracts".  That becomes a "He said. She said" scenario.  "Express contracts" are in writing and need to be specific as to the terms and conditions. 

This is a question that should have been or to be explained to you by your instructor.

I am assuming the answer is in you studies.

I know it is not an Implied Contract.

Plenty of good answers here

Those that are in writing 

Take a look at the contract used in your area.

I think you have answers here, and I wish you good luck.  A

No idea

Good luck with your studies.

I see you got some good examples

I wish you all the best with your studies. 

I am curious as to what the purpose of asking questions in this forum serves for your real estate course?

Beginning to think you need to check your state statutes. And, suggest your instructor do the same.

Others have answered