we have
[tex]I(t)=9t^{-3}+3t^2[/tex]Applying property of exponents
[tex]I(t)=\frac{9}{t^3}+3t^2[/tex]Adds the terms
[tex]\begin{gathered} I(t)=\frac{9+t^3\cdot3t^2}{t^3} \\ \\ I(t)=\frac{3t^5+9}{t^3} \end{gathered}[/tex]we have a rational function
the two polynomials are
numerator ------> 3t^5+9 (binomial of degree 5)
denominator ----> t^3 (monomial of degree 3)