Complex sentence: Kennedy was 9 years old when his uncle President John F. Kennedy was assassinated, and 14 years old when his father was murdered while running for president in the 1968 election.
Split into simpler sentences: Kennedy was 9 years old when his uncle John F. Kennedy was assassinated while serving as president. He was 14 years old when his father was assassinated while running for president in the 1968 election.