**a) $$2^5 \cdot 8$$**
$$2^5 \cdot 8 = 2^5 \cdot 2^3 = 2^{5+3} = 2^8$$
**б) $$16 \cdot 64$$**
$$16 \cdot 64 = 2^4 \cdot 2^6 = 2^{4+6} = 2^{10}$$
**в) $$7^n \cdot 343$$**
$$7^n \cdot 343 = 7^n \cdot 7^3 = 7^{n+3}$$
**г) $$81 \cdot 3^k$$**
$$81 \cdot 3^k = 3^4 \cdot 3^k = 3^{4+k}$$