Chapter 4 - Polynomials - 4.2 Negative Exponents and Scientific Notations - 4.2 Exercise Set - Page 245: 111

$2.5\times10^{13}$

Using the laws of exponents and the concepts of scientific notation, the given expression, $ \dfrac{8.5\times10^8}{3.4\times10^{-5}} $, simplifies to \begin{array}{l} (8.5\div3.4)\times10^{8-(-5)} \\\\= 2.5\times10^{13} .\end{array}