\[ \frac{16(a^3 b^4 )^2}{a^5 b^8} = \frac{16 \cdot (a^3)^2 \cdot (b^4)^2}{a^5 b^8} = \frac{16 \cdot a^{3 \cdot 2} \cdot b^{4 \cdot 2}}{a^5 b^8} = \frac{16 a^6 b^8}{a^5 b^8} \]
\[ 16 \cdot a^{6-5} \cdot b^{8-8} = 16 \cdot a^1 \cdot b^0 = 16a \]
\[ 16 \cdot 2 = 32 \]
Ответ: 32