方法一：
{3X/(X-2)- X/(X+2)}· (4-X²)/ X
 
={3(X+2)- (X-2)}/(X-2) (X+2)·{- (X² -4)}
 
=(3X+6- X+2) /(X-2) (X+2)·{- (X-2) (X+2)}
 
=-(2X+8)
 
=-2X-8
 
方法二：
 
{3X/(X-2)- X/(X+2)}· (4-X²)/ X
 
={3(X+2)- (X-2)}/(X²-4)·{- (X² -4)}
 
=(3X+6- X+2) /(X²-4)·{- (X²-4)}
 
=-(2X+8)
 
=-2X-8