3. 9^-3/2 + 27^-1 / 81^-3/4 + 27^-4/3

9^-3/2 = 1/27
27^-1 = 1/27
81^-3/4 = 1/27
27^-4/3 = 1/81

1/27+1/27=2/27
1/27+1/81 = 4/81

2/27 ÷ 4/81 = 2/27×81/4 = 27/18
= 1 9/18 = 1 1/2