We need to evaluate:
\[
\int \frac{dx}{25-x^2}.
\]
Write
\[
25-x^2=5^2-x^2.
\]
We know the standard formula:
\[
\int \frac{dx}{a^2-x^2}
=
\frac{1}{2a}\log\left|\frac{a+x}{a-x}\right|+c.
\]
Here,
\[
a=5.
\]
Therefore,
\[
\int \frac{dx}{25-x^2}
=
\frac{1}{2(5)}\log\left|\frac{5+x}{5-x}\right|+c.
\]
\[
=
\frac{1}{10}\log\left|\frac{5+x}{5-x}\right|+c.
\]
Hence,
\[
\int \frac{dx}{25-x^2}
=
\frac{1}{10}\log\left|\frac{5+x}{5-x}\right|+c.
\]