1. Solve the inequality $$-6x^2 + 5x + 6 < 0$$.
2. First, find the roots of the quadratic equation $$-6x^2 + 5x + 6 = 0$$ by using the quadratic formula:
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ where $$a = -6$$, $$b = 5$$, and $$c = 6$$.
3. Calculate the discriminant:
$$\Delta = 5^2 - 4(-6)(6) = 25 + 144 = 169$$.
4. Find the roots:
$$x = \frac{-5 \pm \sqrt{169}}{2(-6)} = \frac{-5 \pm 13}{-12}$$.
5. Calculate each root:
- $$x_1 = \frac{-5 + 13}{-12} = \frac{8}{-12} = -\frac{2}{3}$$
- $$x_2 = \frac{-5 - 13}{-12} = \frac{-18}{-12} = \frac{3}{2}$$
6. Since $$a = -6 < 0$$, the parabola opens downward, so the quadratic is less than zero between the roots:
$$-\frac{2}{3} < x < \frac{3}{2}$$.
7. Solve the inequality $$\frac{2}{x} - \frac{1}{x^2} < -3$$.
8. Multiply both sides by $$x^2$$ (noting $$x \neq 0$$) to clear denominators:
$$2x - 1 < -3x^2$$.
9. Rearrange to standard form:
$$3x^2 + 2x - 1 < 0$$.
10. Find roots of $$3x^2 + 2x - 1 = 0$$ using quadratic formula with $$a=3$$, $$b=2$$, $$c=-1$$:
$$\Delta = 2^2 - 4(3)(-1) = 4 + 12 = 16$$.
11. Roots:
$$x = \frac{-2 \pm 4}{2 \cdot 3}$$
- $$x_1 = \frac{-2 + 4}{6} = \frac{2}{6} = \frac{1}{3}$$
- $$x_2 = \frac{-2 - 4}{6} = \frac{-6}{6} = -1$$
12. Since $$a=3 > 0$$, parabola opens upward, so inequality $$3x^2 + 2x - 1 < 0$$ holds between roots:
$$-1 < x < \frac{1}{3}$$.
13. Also, remember $$x \neq 0$$ because of original denominators.
14. Final solution for second inequality:
$$-1 < x < 0$$ or $$0 < x < \frac{1}{3}$$.
**Final answers:**
- For $$-6x^2 + 5x + 6 < 0$$: $$-\frac{2}{3} < x < \frac{3}{2}$$.
- For $$\frac{2}{x} - \frac{1}{x^2} < -3$$: $$-1 < x < 0$$ or $$0 < x < \frac{1}{3}$$.
Quadratic Inequalities
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