Answer: 9/4
Step-by-step explanation: Think of [tex](\frac{4}{9})^{-1}[/tex]as [tex]\frac{4^{-1} }{9^{-1}}[/tex].
Now, we can change 4⁻¹ to 4¹ by moving it to the denominator and
we can change 9⁻¹ to 9¹ by moving it to the numerator.
So we have 9¹/4¹ which simplifies to 9/4.