1. **State the problem:** Solve the equation $$\frac{2}{3}(x - 7)^2 + 5\left(x - \frac{1}{3}\right) + \frac{4}{6} = \frac{2}{3}(x - 1)(x + 1) + \frac{129}{6}$$ for $x$.
2. **Recall formulas and rules:**
- Expand squares and products.
- Combine like terms.
- Use common denominators to simplify fractions.
- Isolate $x$ terms to one side.
- When dividing both sides by a factor, show cancellation.
3. **Expand and simplify each side:**
- Left side:
$$\frac{2}{3}(x - 7)^2 = \frac{2}{3}(x^2 - 14x + 49) = \frac{2}{3}x^2 - \frac{28}{3}x + \frac{98}{3}$$
- The term $5\left(x - \frac{1}{3}\right) = 5x - \frac{5}{3}$
- The term $\frac{4}{6} = \frac{2}{3}$
So left side sum:
$$\frac{2}{3}x^2 - \frac{28}{3}x + \frac{98}{3} + 5x - \frac{5}{3} + \frac{2}{3}$$
Combine constants:
$$\frac{98}{3} - \frac{5}{3} + \frac{2}{3} = \frac{98 - 5 + 2}{3} = \frac{95}{3}$$
Left side becomes:
$$\frac{2}{3}x^2 - \frac{28}{3}x + 5x + \frac{95}{3}$$
Convert $5x$ to thirds:
$$5x = \frac{15}{3}x$$
So left side:
$$\frac{2}{3}x^2 - \frac{28}{3}x + \frac{15}{3}x + \frac{95}{3} = \frac{2}{3}x^2 - \frac{13}{3}x + \frac{95}{3}$$
4. **Right side:**
$$\frac{2}{3}(x - 1)(x + 1) + \frac{129}{6} = \frac{2}{3}(x^2 - 1) + \frac{129}{6} = \frac{2}{3}x^2 - \frac{2}{3} + \frac{129}{6}$$
Convert constants to common denominator 6:
$$-\frac{2}{3} = -\frac{4}{6}$$
Sum constants:
$$-\frac{4}{6} + \frac{129}{6} = \frac{125}{6}$$
Right side becomes:
$$\frac{2}{3}x^2 + \frac{125}{6}$$
5. **Set equation:**
$$\frac{2}{3}x^2 - \frac{13}{3}x + \frac{95}{3} = \frac{2}{3}x^2 + \frac{125}{6}$$
6. **Subtract $\frac{2}{3}x^2$ from both sides:**
$$\frac{2}{3}x^2 - \frac{13}{3}x + \frac{95}{3} - \frac{2}{3}x^2 = \frac{2}{3}x^2 + \frac{125}{6} - \frac{2}{3}x^2$$
Intermediate step with cancellation:
$$\cancel{\frac{2}{3}x^2} - \frac{13}{3}x + \frac{95}{3} - \cancel{\frac{2}{3}x^2} = \cancel{\frac{2}{3}x^2} + \frac{125}{6} - \cancel{\frac{2}{3}x^2}$$
Simplifies to:
$$- \frac{13}{3}x + \frac{95}{3} = \frac{125}{6}$$
7. **Subtract $\frac{95}{3}$ from both sides:**
$$- \frac{13}{3}x + \frac{95}{3} - \frac{95}{3} = \frac{125}{6} - \frac{95}{3}$$
Intermediate step with cancellation:
$$- \frac{13}{3}x + \cancel{\frac{95}{3}} - \cancel{\frac{95}{3}} = \frac{125}{6} - \frac{95}{3}$$
Simplify right side by converting $\frac{95}{3}$ to sixths:
$$\frac{95}{3} = \frac{190}{6}$$
So:
$$\frac{125}{6} - \frac{190}{6} = -\frac{65}{6}$$
Equation becomes:
$$- \frac{13}{3}x = -\frac{65}{6}$$
8. **Solve for $x$ by dividing both sides by $-\frac{13}{3}$:**
$$x = \frac{-\frac{65}{6}}{-\frac{13}{3}} = \frac{-65}{6} \times \frac{3}{-13}$$
Intermediate step with cancellation:
$$x = \frac{\cancel{-65}}{6} \times \frac{3}{\cancel{-13}} = \frac{5}{6} \times 3 = \frac{15}{6}$$
Simplify fraction:
$$\frac{15}{6} = \frac{5}{2}$$
**Final answer:**
$$x = \frac{5}{2}$$
Solve Quadratic E33A66
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