Step 1:
To answer each of the questions, you will apply the multiplication and division laws of the exponent.
[tex]\begin{gathered} \text{Multiplication law} \\ \text{If m}^n\text{ }\times m^t=m^{n+t} \\ \text{Division law} \\ \text{If m}^n\text{ }\frac{.}{.}m^t=m^{n-t} \end{gathered}[/tex]Step 2:
[tex]\begin{gathered} a)5^3\text{ }\times5^{-4}=5^{3-4} \\ =5^{-1} \\ =\text{ }\frac{1}{5} \\ \end{gathered}[/tex]