Question

5^n×25^n-1÷(5^n-1×25^n-1)

Answer 1

{5^n * 5^(2n-2)} / {5^(n-1) * 5^(2n-1)}

as 5^(2n-1) is same in both, it will divide.

(5^n)/(5^(n-1)

as both denominator and numerator has same base(5), 5^(n-1) then after going on numerator this will be minus

then 

5^{n-(n-1)}

5^(n-n+1)

5^1


=5 


i hope this will help you