Simplify the following text for a Grade 9 native English-speaking person.
Original: Marshall Bruce Mathers III ( born October 17 , 1972 ) , better known by his stage name Eminem , is an American rapper , record producer , and actor .
Simplified: Marshall Bruce Mathers III , ( born October 17 , 1972 ) , better known by his stage names Eminem and Slim Shady , is a rap artist from Detroit .