Complex sentence: The Pacers were first established in 1967 as members of the American Basketball Association (ABA) and became members of the NBA in 1976 as a result of the ABA-NBA merger.
Split into simpler sentences: The Pacers were first established in 1967 as members of the American Basketball Association (ABA). They became members of the NBA in 1976 as a result of the ABA-NBA merger.