It has two front chainrings and ten cogs in the rear. A 3x9 has three front chainrings and nine cogs in the rear. Although bikes used to have all types of drivetrains with 5, 6, 7, or other numbers of rear cogs, were going to start our discussion with 9-speed systems.
Neil Sedaka has a long and distinguished career as a pop singer, songwriter, and pianist. His many hits include Breaking Up Is Hard To Do (1962, 1975 slower remake), Laughter In The Rain (1975), and Bad Blood (1975).
This was written and first recorded by Neil Diamond. His original version first appeared on his 1967 album Just For You (Bang 217) and was produced by Jeff Barry and Ellie Greenwich (a.k.a. The Raindrops of The Kind Of Boy You Can't Forget fame). Neil's version of the song (Bang single 556) peaked at #62 over a three-week run in April 1968.