To reduce the rational expression to its lowest terms, we need to factor both the numerator and the denominator and then cancel out any common factors.
Step 1: Factor the Numerator
The numerator \( 5q^2 + 45q + 100 \) can be factored as follows:
\[
5(q + 4)(q + 5)
\]
Step 2: Factor the Denominator
The denominator \( 25q^2 - 25q - 500 \) can be factored as:
\[
25(q - 5)(q + 4)
\]
Step 3: Simplify the Rational Expression
Now, we can write the rational expression as:
\[
\frac{5(q + 4)(q + 5)}{25(q - 5)(q + 4)}
\]
We can cancel the common factor \( (q + 4) \):
\[
\frac{5(q + 5)}{25(q - 5)}
\]
This simplifies to:
\[
\frac{q + 5}{5(q - 5)}
\]
Final Answer
The reduced form of the rational expression is:
\[
\boxed{\frac{q + 5}{5(q - 5)}}
\]