1. **State the problem:** Solve the inequality $$x^3 - 6x^2 + 11x - 6 < 0$$.
2. **Factor the cubic polynomial:** To solve the inequality, first factor the cubic expression. We look for rational roots using the Rational Root Theorem. Possible roots are factors of 6: $\pm1, \pm2, \pm3, \pm6$.
3. **Test roots:**
- For $x=1$: $$1^3 - 6(1)^2 + 11(1) - 6 = 1 - 6 + 11 - 6 = 0$$ so $x=1$ is a root.
4. **Divide the polynomial by $(x-1)$:**
$$\frac{x^3 - 6x^2 + 11x - 6}{x-1} = x^2 - 5x + 6$$
5. **Factor the quadratic:**
$$x^2 - 5x + 6 = (x-2)(x-3)$$
6. **Complete factorization:**
$$x^3 - 6x^2 + 11x - 6 = (x-1)(x-2)(x-3)$$
7. **Analyze the inequality:**
We want to find where
$$(x-1)(x-2)(x-3) < 0$$
8. **Determine sign intervals:**
- For $x < 1$, all three factors are negative or positive?
- $(x-1)<0$, $(x-2)<0$, $(x-3)<0$ so product is $(-)(-)(-) = -$ negative.
- For $1 < x < 2$:
- $(x-1)>0$, $(x-2)<0$, $(x-3)<0$ so product is $(+)(-)(-) = +$ positive.
- For $2 < x < 3$:
- $(x-1)>0$, $(x-2)>0$, $(x-3)<0$ so product is $(+)(+)(-) = -$ negative.
- For $x > 3$:
- $(x-1)>0$, $(x-2)>0$, $(x-3)>0$ so product is $(+)(+)(+) = +$ positive.
9. **Solution:** The inequality holds where the product is negative:
$$x < 1 \quad \text{or} \quad 2 < x < 3$$
**Final answer:** $$(-\infty, 1) \cup (2, 3)$$
Cubic Inequality 120C1B
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