Chapter 5 - Section 5.2 - More Work with Exponents and Scientific Notation - Exercise Set - Page 268: 86

$9.6\times10^{5}$

Using laws of exponents, the given expression simplifies to \begin{align*} & \dfrac{(2.6\times10^{-3})(4.8\times10^{-4})}{1.3\times10^{-12}} \\\\&= (2.6\times4.8\div1.3)(10^{-3}\times10^{-4}\div10^{-12}) \\\\&= 9.6\times10^{-3+(-4)-(-12)} \\\\&= 9.6\times10^{5} .\end{align*}