In attempting to research a contract law question I am confused about whether I should check the first or second resource (listed below) first.

In attempting to research a contract law question I am confused about whether I should check the first or second resource (listed below) first. Or perhaps I would only need to check one of the two because the UCC is valid for contracts in all states except Louisiana and the case I am researching is not in Louisiana.

A) Uniform Commercial Code

B) RCW (WA state) as it addresses and/or incorporates the UCC.