Question

5n×25n-1÷(5n-1×25n-1)​

Answer 1

5n-n+1×25n-1-n+1

5n×50

5

Answer 2

125n - 1 ÷ {125n -2}

$\frac{125n - 1}{125n - 2} = \frac{1}{2}$

This way 125n will be cut by 125n and - with - and the answer comes 1/2.

Hope it helps.