[tex]\text{Scientific notation:}\ a\cdot10^k\\\\\text{where}\ 1\leq a<10\ \text{and}\ k\in\mathbb{Z}.\\\\\text{Use}\ \dfrac{a^n}{a^m}=a^{n-m}.\\\\-------------------------\\\\\dfrac{3.6\cdot10^{-5}}{4.8\cdot10^{-7}}=\dfrac{3.6}{4.8}\cdot\dfrac{10^{-5}}{10^{-7}}=0.75\cdot10^{-5-(-7)}=0.75\cdot10^{-5+7}\\\\=0.75\cdot10^2=7.5\cdot10^{-1}\cdot10^2=7.5\cdot10^{-1+2}=\boxed{7.5\cdot10}[/tex]
