Actually Welcome to the Concept of the exponents and indices.
here, we should remember one thing that,
3 ^3 = 27 and 1/3^x = 3^-x
so we get as,
(3^-3)^4-x = (3^3)^2x-1
==> 3^-12+3x = 3^6x-3
since the base is same that is 3 , we equate their powers.
-12x+3=6x-3
==> 3+3 = 6x+12x
==> 6 = 18x
hence ===> x = 6/18 = 1/3
hence, x = 1/3