Answer
$3.4 \times 10^{-5}$
Work Step by Step
$a^m \cdot a^n = a^{m+n}$
Multiply the corresponding parts and use the rule above when necessary to find the answer:
$=(1\cdot 3.4) \times (10^3 \cdot 10^{-8})
\\=3.4 \times 10^{3+{-8}}
\\=3.4 \times 10^{-5}$
