∵8^m=12
∴2^(3m)=12
∵4^n=6
∴2^(2n)=6
2^(6m-2n+1)
=[2^(6m)]÷[2^(2n)]×2
=[2^(3m)]²÷[2^(2n)]×2
=12²÷6×2
=144÷6×2
=24×2
=48