To solve the given integral, we can use a substitution method to simplify the expression under the square root. A trigonometric substitution might be appropriate here due to the form of the expression \( \sqrt{25x^2 - 4} \). After substitution, the integral can be evaluated, and then the result can be transformed back to the original variable.
Step 1: Define the Integral
We need to evaluate the definite integral
\[
I = \int_{2/5}^{4/5} \frac{\sqrt{25x^2 - 4}}{x} \, dx.
\]
Step 2: Evaluate the Integral
After applying the appropriate substitution and evaluating the integral, we find that