Explanation
We are given the expression below:
[tex]\frac{1}{a^{-4}}[/tex]We are required to rewrite the expression without a negative exponent.
This can be achieved thus:
[tex]\begin{gathered} \frac{1}{a^{-4}} \\ We\text{ }know\text{ }from\text{ }indices\text{ }that\text{ }a^{-x}=\frac{1}{a^x} \\ \therefore\frac{1}{a^{-4}}=1\div a^{-4}=1\div\frac{1}{a^4} \\ =1\times\frac{a^4}{1}=a^4 \end{gathered}[/tex]Hence, the answer is a⁴.