Answer :

To simplify the expression [tex]\( 5^{-\frac{5}{2}} \cdot 5^{\frac{9}{2}} \)[/tex], we can use the properties of exponents. Specifically, we can use the exponent rule for multiplying powers with the same base, which states:

[tex]\[ a^m \cdot a^n = a^{m+n} \][/tex]

In this case, the base [tex]\(a\)[/tex] is 5, and the exponents are [tex]\(-\frac{5}{2}\)[/tex] and [tex]\(\frac{9}{2}\)[/tex].

Step-by-step, we proceed as follows:

1. Combine the Exponents:
[tex]\[ 5^{-\frac{5}{2}} \cdot 5^{\frac{9}{2}} = 5^{-\frac{5}{2} + \frac{9}{2}} \][/tex]

2. Add the Exponents:
[tex]\[ -\frac{5}{2} + \frac{9}{2} = \frac{9}{2} - \frac{5}{2} = \frac{9 - 5}{2} = \frac{4}{2} = 2 \][/tex]

3. Simplify the Expression:
[tex]\[ 5^{-\frac{5}{2} + \frac{9}{2}} = 5^2 \][/tex]

4. Calculate the Final Value:
[tex]\[ 5^2 = 25 \][/tex]

Thus, the simplified value of the expression [tex]\( 5^{-\frac{5}{2}} \cdot 5^{\frac{9}{2}} \)[/tex] is [tex]\( 25 \)[/tex].

Therefore, the correct answer is:
[tex]\[ \boxed{25} \][/tex]