(a/b)^n=2 (a/b)^3n=【(a/b)^n】^3=2^3=8 (b/a)^m=3 所以(a/b)^m=1/3 (a/b)^2m=【(a/b)^m】^2=(1/3)^2=1/9 (a/b)^2m+3n =(a/b)^3n * (a/b)^2m =8*1/9 =8/9
