![5girls amber_josephine_liu black_hair brown_hair choi_jinri circle_formation closed_eyes f(x) holding_hands jung_soo-jung long_hair lying meryl_santos multiple_girls on_back park_sunyoung short_hair short_sleeves shorts smile song_qian star star_hands white_background rating:s score:0 post #1002234](/cdn_image/preview/92/59/925910a1ac7833f65f56d373735cd7c4.jpg)
f(x) (Korean: 에프엑스; pronounced /ˌɛf ˈɛks/) is a five member South Korean girl group formed by SM Entertainment in 2009. The name is a play on the mathematical notation for function, and when input with different 'x', there can be many different outcomes. f(x) strives to be the kind of girl group that can change and adapt to many situations. The group members have also been nicknamed "function girls". The quintet consists of Victoria, Amber, Luna, Sulli and Krystal.