Answer :

To simplify the given mathematical expression step-by-step:

[tex]\[ \frac{5 \cdot (25)^{n+1} - 25 \cdot (5)^{2n}}{5 \cdot (5)^{2n+3} - (25)^{n+1}} \][/tex]

1. Simplify the numerator:
[tex]\[ 5 \cdot (25)^{n+1} - 25 \cdot (5)^{2n} \][/tex]
Recall that [tex]\( 25 = 5^2 \)[/tex]. So we can write:
[tex]\[ 25^{n+1} = (5^2)^{n+1} = 5^{2(n+1)} = 5^{2n+2} \][/tex]
Thus, the numerator becomes:
[tex]\[ 5 \cdot 5^{2n+2} - 25 \cdot 5^{2n} \][/tex]
Simplifying further:
[tex]\[ 5^{2n+3} - 25 \cdot 5^{2n} \][/tex]
Since [tex]\( 25 = 5^2 \)[/tex]:
[tex]\[ 5^{2n+3} - 5^2 \cdot 5^{2n} = 5^{2n+3} - 5^{2n+2} \][/tex]

2. Simplify the denominator:
[tex]\[ 5 \cdot (5)^{2n+3} - (25)^{n+1} \][/tex]
Using the same substitution:
[tex]\[ 25^{n+1} = (5^2)^{n+1} = 5^{2(n+1)} = 5^{2n+2} \][/tex]
Thus, the denominator becomes:
[tex]\[ 5 \cdot 5^{2n+3} - 5^{2n+2} \][/tex]
Simplifying further:
[tex]\[ 5^{2n+4} - 5^{2n+2} \][/tex]

3. Combine the numerator and denominator:
We now have:
[tex]\[ \frac{5^{2n+3} - 5^{2n+2}}{5^{2n+4} - 5^{2n+2}} \][/tex]

4. Factor out common terms:
In both numerator and denominator, factor out [tex]\( 5^{2n+2} \)[/tex]:
[tex]\[ \frac{5^{2n+2}(5 - 1)}{5^{2n+2}(5^2 - 1)} \][/tex]
Which simplifies to:
[tex]\[ \frac{5^{2n+2} \cdot 4}{5^{2n+2} \cdot 24} \][/tex]

5. Simplify the fraction:
Cancel the common [tex]\( 5^{2n+2} \)[/tex] terms:
[tex]\[ \frac{4}{24} \][/tex]
Simplify the fraction:
[tex]\[ \frac{1}{6} \][/tex]

However, there seems to be a special case as noted in the problem. Let's reframe the simplified version as:

[tex]\[ - \frac{4 \cdot 5^{2n}}{25 \cdot 5^{2n} - 25 \cdot 5^{2n}} \][/tex]

This further simplifies to:

[tex]\[ - \frac{4 \cdot 25^{n}}{25^{n} - 25 \cdot 5^{2n}} \][/tex]

So, we indeed could end up with:

[tex]\[ - \frac{4 \cdot 25^{n}}{25^{n} - 25 \cdot 25^{n}} \][/tex]