How do you simplify 3^-1*3^3 and write it using only positive exponents?

${3}^{2}$
Using the $\textcolor{b l u e}{\text{law of exponents}}$
$\textcolor{\mathmr{and} a n \ge}{\text{Reminder }} \textcolor{red}{\overline{\underline{| \textcolor{w h i t e}{\frac{2}{2}} \textcolor{b l a c k}{{a}^{m} \times {a}^{n} = {a}^{m + n}} \textcolor{w h i t e}{\frac{2}{2}} |}}}$
$\Rightarrow {3}^{-} 1 \times {3}^{3} = {3}^{\left(- 1 + 3\right)} = {3}^{2} = 9$