∵|3a+1|与(b-2）²互为相反数,
∴ |3a+1|+(b-2）²＝0
∴|3a+1|＝0,(b-2）²＝0
3a+1=0,b-2=0
∴a=-1/3,b=2
∴A^B-AB
=(-1/3)²-(-1/3)×2
=(1/9)+(2/3)
=7/9