Chapter 7 - Exponents and Exponential Functions - 7-3 Multipying Powers with the Same Base - Practice and Problem-Solving Exercises - Page 429: 33

$5.6 \times 10^{-7}$

$a^m \cdot a^n = a^{m+n}$ Multiply the corresponding parts and use the rule above to obtain: $=(8\cdot 7) \times (10^{-5} \cdot 10^{-3}) \\=56 \times 10^{(-5)+{-3}} \\=56 \times 10^{-8} \\=(5.6)(10) \times 10^{-8} \\=5.6 \times 10^{1+(-8)} \\=5.6 \times 10^{-7}$