Simplify the following text for a Grade 5 native English-speaking person.
Original: Then Æ ' ( g ( x ) ) = x for all x in ( 0 , â ) ; that is , g is a right inverse to Æ ' .
Simplified: This is usually written f ( x ) = y. The inverse function does the reverse . Let 's say g is the inverse function of f , then g ( y ) = x. Or otherwise put , f ( g ( x ) ) = x.