What you actually did here is to interpret the negative exponent immediately. If I were teaching this, I would have added an intermediate step or two:how does the negative sign work and/or where does it go?
Does the negative sign go to the exponent or radical?
Note, I haven't actually used the negative sign in my solution,..
Simplify:
(81)^(-3/2)
1/(sqr 81)^3
1/(9)^3
1/729
Actually, you have.… haven't actually used the negative sign in my solution…
(81)^(-3/2)
1/(sqr 81)^3