(x^-3y/x^2)^-3
You should use brackets to clarify the order of operation.
I will assume you mean
( (x^-3)y)/x^2)^-3
= ( (y/x^3)/x^2)^-3
= (y/x^5)^-3
= ((x^5)/y)^3
= x^15 / y^3
I will assume you mean
( (x^-3)y)/x^2)^-3
= ( (y/x^3)/x^2)^-3
= (y/x^5)^-3
= ((x^5)/y)^3
= x^15 / y^3