Step 1: Solving the non-homogeneous differential equation.
The given equation is a second-order linear differential equation with constant coefficients. We solve the corresponding homogeneous equation and then find the particular integral using the method of undetermined coefficients.
Step 2: Finding the particular integral.
The correct form of the particular integral is \( e^{ex} e^{-2x} \), as determined by the method of undetermined coefficients.
Step 3: Conclusion.
The correct answer is (B) \( e^{ex} e^{-2x} \).
Let \( f : [1, \infty) \to [2, \infty) \) be a differentiable function. If
\( 10 \int_{1}^{x} f(t) \, dt = 5x f(x) - x^5 - 9 \) for all \( x \ge 1 \), then the value of \( f(3) \) is ______.