Simplify the following text for a Grade 9 native English-speaking person.
Original: He won two National Basketball Association ( NBA ) championships with the Houston Rockets .
Simplified: From 1984 to 2002 , he played in the National Basketball Association ( NBA ) as a member of the Houston Rockets and Toronto Raptors . He led the Rockets to back-to-back NBA championships in 1994 and 1995 .