(2x-3y)的n次方×(3y-2x)的2n+1次方=
(2x-3y)的n次方×(3y-2x)的2n次方×(3y-2x)=
(2x-3y)的n次方×(2x-3y)的2n次方×(3y-2x)=
(2x-3y)的3n次方×[-(2x-3y))]=
-(2x-3y)的3n+1次方