6) [(-3)³*3^5] / (-3)^9 = (- 3^8) / (- 3^9) = 1/3
7 )(2/3)^(-4) - (1/√6)^(-2) = 81/16 - 6 = 5,0625 - 6 = - 0,9375
8) [3^(-1) - (2/3)^(-2)] / (2 - (3/4)²) * (5° - 1/6)^(-1) + 2 * 10^(-1) =
= (1/3 - 9/4) / (2 - 9/16) * (1 - 1/6)^(-1) + 0,2 = (- 23/12) / (23/16) * 6/5 + 0,2 = - 8/5 + 0,2 = - 1,4
9) (256/81) ^(- 1/4) = (81/256)^(1/4) = 3/4 = 0,75