Rewrite with positive exponents assume that even roots are nonegative quantitives and that all demoninators are nonzeros.
(6xy/y)-3
Assuming you meant to type
(6xy/y)^-3
= (6x)^-3
= (1/6x)^3
= 1/(216x^3)
(6xy/y)-3
(6xy/y)^-3
= (6x)^-3
= (1/6x)^3
= 1/(216x^3)