Đáp án:

• Đặt \( t = x^2 \)

• \( I =\frac{1}{2} \int \frac{t - 3}{t (t^2 + 3t + 2)} \, dt = \frac{1}{2} \int \frac{t - 3}{t (t + 1)(t + 2)} \, dt  \)

• \( \frac{t - 3}{t (t + 1)(t + 2)} = \frac{A}{t} + \frac{B}{t + 1} + \frac{C}{t + 2} \implies  
\begin{cases} 
A = -\frac{3}{2} \\ 
B = 4 \\ 
C = -\frac{5}{2} 
\end{cases} \)