A)
7/4 * 2/7 = 14/28 = 1/2
(1/2)^6 = 1/64
B)
8/10 : 8/3 = 8/10 * 3/8 = 24/80 = 3/10
(3/10)^4 = 81/10000
C)
9/2 * (-2/3) * (-2) = - 18/6 * (-2/1) = 36/6 = 6
6^3 = 216
D)
5/2 * 6/10 : (-15/1) = 3/2 * (- 1/15) = - 3/30 = - 1/10
(-1/10)^4 = 1/10000