Im a british citizen who was born in the states have a parent from each and both passports im moving to the us in 3 weeks what passport do you use?

you can use either since there is a visa waiver program with UK, the problem is that if you enter with the british passport you will be treated as an alien, and you will have to leave the country as a british citizen even if you hold an American citizenship, i know that it doesnt make much sense, but that's how things are, in case of doubt check with the American embassy

ANSWER:

If you are an American Citizen you are required to enter and leave the US on your American Passport, regardless of other citizenships or passports you may hold.