How were future new states to decide if they entered the Union as a free or slave state

Answer 1

4 federal laws apply:

1) Northwest Ordinance (1787)--Old Northwest Territories

2) Missouri Compromise (1820) Missouri, Maine, and Louisiana Purchase territory.

3) Compromise of 1850 (1850)--Mexican Cession Territory

4) Kansas-Nebraska Act (1854) --Kansas and Nebraska

Research the above for their contents. You'll find the answers in any textbook--just use the index.