Use a combination of rules for exponents to simplify the expression to exponential form with only positive exponents. Assume variables represent nonzero real numbers.
(2x^-3y/3^-1z^4)^-2
(2x^-3y/3^-1z^4)^-2
= (2x^-3y/(1/3)z^4)^-2
= (2x^-3y/1z^4/3)^-2
= (2x^-3y/3z^4)^-2
= ((2/3)x^-3yz^-4)^-2
= (2/3)^-2 x^6y^-2z^8
= (3/2)^2 x^6y^2z^8
= (3/2)^2 x^6y^2z^8
Therefore, the expression in exponential form with only positive exponents is (3/2)^2 x^6y^2z^8.