Final answer:
British colonists were motivated to settle west of the Appalachians mostly by the availability of fertile and affordable land, hoping to expand agriculture and farming opportunities.
Step-by-step explanation:
In the eighteenth century, British colonists wishing to settle west of the Appalachians were principally motivated by the low price and easy availability of land. The British victory in the French and Indian War had led to expectations that colonists would be able to claim the fertile lands of the Ohio Valley. New England families needed more land for their growing generations, and southern colonists sought new territories for tobacco farming due to the exhausted fertility of lands along the Chesapeake Bay. However, the British government, eager to avoid conflict with Native American tribes and maintain control over its colonists, passed the Proclamation of 1763, which prohibited settlement west of the Appalachians, much to the colonists' frustration.