1. **State the problem:** Solve the inequality $$\frac{x^2 - 2x - 8}{x^3 + x} \geq 0$$.
2. **Factor numerator and denominator:**
- Numerator: $$x^2 - 2x - 8 = (x - 4)(x + 2)$$
- Denominator: $$x^3 + x = x(x^2 + 1)$$
3. **Analyze denominator:**
- Since $$x^2 + 1 > 0$$ for all real $$x$$, the sign of the denominator depends only on $$x$$.
4. **Rewrite inequality:**
$$\frac{(x - 4)(x + 2)}{x(x^2 + 1)} \geq 0 \implies \frac{(x - 4)(x + 2)}{x} \geq 0$$
5. **Find critical points:**
- Numerator zeros: $$x = 4, -2$$
- Denominator zero: $$x = 0$$ (excluded from domain)
6. **Determine sign intervals:**
- Intervals: $$(-\infty, -2), (-2, 0), (0, 4), (4, \infty)$$
7. **Test each interval:**
- For $$x < -2$$, choose $$x = -3$$:
$$\frac{(-3 - 4)(-3 + 2)}{-3} = \frac{(-7)(-1)}{-3} = \frac{7}{-3} < 0$$
- For $$-2 < x < 0$$, choose $$x = -1$$:
$$\frac{(-1 - 4)(-1 + 2)}{-1} = \frac{(-5)(1)}{-1} = \frac{-5}{-1} = 5 > 0$$
- For $$0 < x < 4$$, choose $$x = 1$$:
$$\frac{(1 - 4)(1 + 2)}{1} = (-3)(3) = -9 < 0$$
- For $$x > 4$$, choose $$x = 5$$:
$$\frac{(5 - 4)(5 + 2)}{5} = (1)(7)/5 = 7/5 > 0$$
8. **Include zeros where numerator is zero:**
- At $$x = -2$$ and $$x = 4$$, numerator is zero, so expression equals zero.
- At $$x = 0$$, denominator zero, undefined.
9. **Solution:**
$$[-2, 0) \cup [4, \infty)$$
**Final answer:**
$$\boxed{[-2, 0) \cup [4, \infty)}$$
Rational Inequality A52De6
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.