1. **State the problem:** Solve the inequality $$\frac{3x^2}{5} + \frac{x}{4} - (x - 2) - \frac{1}{2}\left(x - \frac{1}{2}\right) \geq \left(\frac{x - 1}{2}\right)^2 + \frac{3x}{5}(x - 1).$$
2. **Rewrite the inequality clearly:**
$$\frac{3x^2}{5} + \frac{x}{4} - (x - 2) - \frac{1}{2}\left(x - \frac{1}{2}\right) \geq \left(\frac{x - 1}{2}\right)^2 + \frac{3x}{5}(x - 1).$$
3. **Expand and simplify each term:**
- Left side:
$$\frac{3x^2}{5} + \frac{x}{4} - x + 2 - \frac{1}{2}x + \frac{1}{4}$$
Combine like terms:
$$\frac{3x^2}{5} + \left(\frac{x}{4} - x - \frac{1}{2}x\right) + \left(2 + \frac{1}{4}\right) = \frac{3x^2}{5} + \left(\frac{x}{4} - \frac{3x}{2}\right) + \frac{9}{4}.$$
4. **Simplify the x terms:**
$$\frac{x}{4} - \frac{3x}{2} = \frac{x}{4} - \frac{6x}{4} = -\frac{5x}{4}.$$
So left side is:
$$\frac{3x^2}{5} - \frac{5x}{4} + \frac{9}{4}.$$
5. **Right side:**
$$\left(\frac{x - 1}{2}\right)^2 + \frac{3x}{5}(x - 1) = \frac{(x - 1)^2}{4} + \frac{3x(x - 1)}{5}.$$
Expand:
$$\frac{x^2 - 2x + 1}{4} + \frac{3x^2 - 3x}{5}.$$
6. **Find common denominators and combine right side:**
Multiply first term by 5/5 and second by 4/4:
$$\frac{5(x^2 - 2x + 1)}{20} + \frac{4(3x^2 - 3x)}{20} = \frac{5x^2 - 10x + 5 + 12x^2 - 12x}{20} = \frac{17x^2 - 22x + 5}{20}.$$
7. **Rewrite inequality:**
$$\frac{3x^2}{5} - \frac{5x}{4} + \frac{9}{4} \geq \frac{17x^2 - 22x + 5}{20}.$$
8. **Multiply both sides by 20 to clear denominators:**
$$20 \times \left(\frac{3x^2}{5} - \frac{5x}{4} + \frac{9}{4}\right) \geq 17x^2 - 22x + 5.$$
Calculate left side:
$$20 \times \frac{3x^2}{5} = 12x^2,$$
$$20 \times -\frac{5x}{4} = -25x,$$
$$20 \times \frac{9}{4} = 45.$$
So:
$$12x^2 - 25x + 45 \geq 17x^2 - 22x + 5.$$
9. **Bring all terms to one side:**
$$12x^2 - 25x + 45 - 17x^2 + 22x - 5 \geq 0,$$
Simplify:
$$-5x^2 - 3x + 40 \geq 0.$$
10. **Multiply both sides by -1 (remember to flip inequality):**
$$5x^2 + 3x - 40 \leq 0.$$
11. **Solve quadratic inequality:**
Find roots of
$$5x^2 + 3x - 40 = 0.$$
Use quadratic formula:
$$x = \frac{-3 \pm \sqrt{3^2 - 4 \times 5 \times (-40)}}{2 \times 5} = \frac{-3 \pm \sqrt{9 + 800}}{10} = \frac{-3 \pm \sqrt{809}}{10}.$$
12. **Approximate roots:**
$$\sqrt{809} \approx 28.44,$$
So roots are approximately:
$$x_1 = \frac{-3 - 28.44}{10} = -3.144,$$
$$x_2 = \frac{-3 + 28.44}{10} = 2.544.$$
13. **Determine solution interval:**
Since leading coefficient $5 > 0$, parabola opens upward, so inequality $\leq 0$ holds between roots:
$$-3.144 \leq x \leq 2.544.$$
**Final answer:**
$$\boxed{-\frac{3 + \sqrt{809}}{10} \leq x \leq \frac{-3 + \sqrt{809}}{10}}.$$
Quadratic Inequality 99D294
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