a)2.4.16.32.$2^{3}$
=2.$2^{2}$.$2^{4}$.$2^{5}$.$2^{3}$
=$2^{15}$
b)9.$3^{2}$.$\frac{1}{81}$ .27
=$3^{2}$.$3^{2}$.$\frac{1}{3^4}$ .$3^{3}$
=$3^{4}$.$3^{7}$
=$3^{11}$
c)(4.$2^{5}$):($2^{8}$.$\frac{1}{16}$)
=($2^{2}$.$2^{5}$):($2^{8}$.$\frac{1}{2^4}$)
=$2^{7}$:$2^{4}$
=$2^{3}$