How to get rid of a negative exponent in a fraction?

So let's say we have (3/2) ^-2. We know that any negative exponent means we have to put that number under 1, with a positive exponent:

1 / (3/2) ^2

There's also another thing we can do. There's a rule in maths that says we can get the positive exponent if we just flip the fraction, so we get:

(3/2) ^-2

Flip it:

(2/3) ^2

It would be the same as 1 / (3/2) ^2, since that would be 1/1 / 9/4, resulting in 4/9 (multiply inner part with inner part (9*1) and that goes under, and outer with outer (4*1) and that goes over). (2/3) ^2 is also 4/9, so both ways are valid.