[SOLVED] Need help with exponents: simplifying 1

Hello, I was wondering if someone can tell me if I did these exponent problems right? I'm a bit confused.

Convert the following to equivalent forms in which no negative exponents appear:

a. (2/5)^-1 ---------- I said this equals -2/-5, which is 2/5

b. 6/x^-2 (just the x is to the negative 2) ------ I said this was 6^2/x, which is 36/x

c. (-3/2)^-3 --------- I said this was 81/-8, or -81/8

d. 6xy/3x^-1y-2) (that looks weird anyway 6xy over 3 x to the negative one, y to the negative 2) ---- I was confused. I said 2x^2y^3 (2xsquaredycubed)

e. (2x2/3x-1)^-2 -- I said this was -4x-4/-9x2 = 4x/9x^6.

Note that x is the variable, not multiplication.

Thanks!!

Also, is x^3 times x^-3 x^0?

Thank you so much