fx f(x) (/ˌɛf ˈɛks/; Korean: 에프엑스) is a South Korean girl group formed by SM Entertainment in 2009. The quintet consists of Victoria, Amber, Luna, Sulli, and Krystal. The group made their debut on September 5, 2009, with release of the digital single "LA chA TA". They are known for their consistent sound in releases, with their music being very electronic. f(x) released their first EP Nu ABO in 2010 to growing popularity. They released their first studio album Pinocchio in 2011. The lead single off the album "Pinocchio (Danger)" gained their first music program win and was their first song to win the triple crown. Their band name, f(x) originates from the mathematics' notation meaning function, f(x).
They released their second EP Electric Shock on June 10, 2012. Electric Shock reached the number one spot on both the US and Canadian iTunes electronic albums chart soon after its release. The lead single off their EP gained significant popularity and acclaim, domestically sweeping digital charts. They are currently preparing for their second studio album, which is set to be released on July 29, 2013.