1) b^2 : b^(-1/2) = b^(2-(-1/2)) = b^(5/2)
2) c^(-1/2) * c^(-1/3) = c^(-1/2-1/3) = c^(-3/6-2/6) = c^(-5/6)
3) (b^(1/5))^(-1/2) = b^((1/5)*(-1/2)) = b^(-1/10)
4) d^(-1/5) * d^(1/2) = d^(-1/5+1/2) = d^(-2/10+5/10) = d^(3/10)
5) a^(2/3) * a^(1/6) = a^(2/3+1/6) = a^(4/6+1/6) = a^(5/6)
6) a^(2/3) : a^(-1/6) = a^(2/3-(-1/6)) = a^(2/3+1/6) = a^(5/6)