Question 550751
You may be reading the question wrong. Or you may have the right answers, but may be posting the wrong question.
2. (3xy^-2)/(x^3)^2 ={{{(3xy^-2)/(x^3)^2=(3x/(x^3)^2)(y^-2)=(3x/x^6)(1/y^2)=3/x^5y^2}}}
That is different from
(3xy^-2/x^3)^2={{{(3xy^-2/x^3)^2=3^2x^2(y^-2)^2/(x^3)^2=3^2x^2y^-4/x^6=9/x^4y^4}}}= 9/(x^4y^4)
(I'm using parentheses so it's not understood as 9/(x^4)(y^4) = {{{(9/x^4)y^4=9y^4/x^4}}} ).
4. (-a^2b)/(2b^-1)^3={{{(-a^2b)/(2b^-1)^3=-a^2b/2^3(b^-1)^3=-a^2b/8b^-3=-a^2bb^3/8=-a^2b^4/8}}}
That is different from  (-a^2b/2b^-1)^3={{{(-a^2b/2b^-1)^3=(-a^2)^3b^3/2^3(b^-1)^3=(-a^6)b^3/8b^-3=-a^6b^3b^3/8=-a^6b^6/8}}}
6. (4x)/(y3)^-3={{{(4x)/(y3)^-3=4x/y^-9=4xy^9}}}
That is different from
(4x/y3)^-3={{{(4x/y3)^-3=4^-3x^-3/(y^3)^-3=4^-3x^-3/y^-9=y^9/4^3x^3=y^9/64x^3}}} =y^9/(64x^3)