Express root(125^x)/5^(2x-1) in terms of 5^a where a is an expression in terms of x.

root(125^x) = 125^(x/2) = 5^(3x/2)
5^(3x/2) / 5^(2x-1) = 5^(3x/2 - 2x +1) = 5^(-x/2 + 1)