1) 2 · 256^ 1/5 · 256^ 1/20 = 2 · 256 ^ 1/4 = 2 · (4^4) ^ 1/4 = 2 · 4 = 8
2) 8^ 0.28 · 16^ 0.04 = 2^ (3 · 0.28) + 2^ (4 · 0.04) = 2(0.84 + 0.16) = 2^1 = 2
3) 1.25 = 5/4
(5/4)^ 2/7 · 2^ 6/7 · 10^ 5/7 = 5^ 2/7 · 2^ -4/7 · 2^ 6/7 · 2^ 5/7 · 5^ 5/7 =
= 2^ (-4/7 + 6/7 + 5/7) · 5^ (2/7 + 5/7) = 2^ (7/7) · 5^ (7/7) = 2 · 5 = 10