Equation Solving Cf76A5
1. **Problem a:** Solve the equation $$\frac{6}{x - 1} = \frac{x}{x^2 + 2x + 1}$$
2. **Step 1:** Recognize that $$x^2 + 2x + 1 = (x + 1)^2$$.
3. **Step 2:** Cross-multiply to eliminate denominators:
$$6(x + 1)^2 = x(x - 1)$$
4. **Step 3:** Expand both sides:
$$6(x^2 + 2x + 1) = x^2 - x$$
$$6x^2 + 12x + 6 = x^2 - x$$
5. **Step 4:** Bring all terms to one side:
$$6x^2 + 12x + 6 - x^2 + x = 0$$
$$5x^2 + 13x + 6 = 0$$
6. **Step 5:** Solve the quadratic equation using the quadratic formula:
$$x = \frac{-13 \pm \sqrt{13^2 - 4 \cdot 5 \cdot 6}}{2 \cdot 5} = \frac{-13 \pm \sqrt{169 - 120}}{10} = \frac{-13 \pm \sqrt{49}}{10}$$
7. **Step 6:** Calculate the roots:
$$x = \frac{-13 + 7}{10} = \frac{-6}{10} = -0.6$$
$$x = \frac{-13 - 7}{10} = \frac{-20}{10} = -2$$
8. **Step 7:** Check for restrictions: denominators cannot be zero.
- For $$x - 1 \neq 0$$, so $$x \neq 1$$.
- For $$(x + 1)^2 \neq 0$$, so $$x \neq -1$$.
Both solutions $$x = -0.6$$ and $$x = -2$$ are valid.
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9. **Problem b:** Solve the equation $$\frac{2}{x^2 - 1} + \frac{1}{x + 1} = 1$$
10. **Step 1:** Factor denominator:
$$x^2 - 1 = (x - 1)(x + 1)$$
11. **Step 2:** Find common denominator $$ (x - 1)(x + 1) $$ and rewrite terms:
$$\frac{2}{(x - 1)(x + 1)} + \frac{1}{x + 1} = 1$$
12. **Step 3:** Express $$\frac{1}{x + 1}$$ with common denominator:
$$\frac{1}{x + 1} = \frac{x - 1}{(x - 1)(x + 1)}$$
13. **Step 4:** Combine fractions:
$$\frac{2 + (x - 1)}{(x - 1)(x + 1)} = 1$$
$$\frac{x + 1}{(x - 1)(x + 1)} = 1$$
14. **Step 5:** Simplify numerator and denominator:
$$\frac{x + 1}{(x - 1)(x + 1)} = \frac{1}{x - 1} = 1$$
15. **Step 6:** Solve for $$x$$:
$$\frac{1}{x - 1} = 1 \implies x - 1 = 1 \implies x = 2$$
16. **Step 7:** Check restrictions:
$$x^2 - 1 \neq 0 \implies x \neq \pm 1$$
Solution $$x = 2$$ is valid.
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17. **Problem 13:** Solve $$x\sqrt{7} = x\sqrt{2} + 4\sqrt{2}$$
18. **Step 1:** Rearrange terms:
$$x\sqrt{7} - x\sqrt{2} = 4\sqrt{2}$$
19. **Step 2:** Factor $$x$$:
$$x(\sqrt{7} - \sqrt{2}) = 4\sqrt{2}$$
20. **Step 3:** Solve for $$x$$:
$$x = \frac{4\sqrt{2}}{\sqrt{7} - \sqrt{2}}$$
21. **Step 4:** Rationalize denominator:
$$x = \frac{4\sqrt{2}(\sqrt{7} + \sqrt{2})}{(\sqrt{7} - \sqrt{2})(\sqrt{7} + \sqrt{2})} = \frac{4\sqrt{2}(\sqrt{7} + \sqrt{2})}{7 - 2} = \frac{4\sqrt{2}(\sqrt{7} + \sqrt{2})}{5}$$
22. **Step 5:** Simplify numerator:
$$4\sqrt{2} \cdot \sqrt{7} = 4\sqrt{14}$$
$$4\sqrt{2} \cdot \sqrt{2} = 4 \times 2 = 8$$
23. **Step 6:** Write final answer:
$$x = \frac{8 + 4\sqrt{14}}{5}$$
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**Final answers:**
- a) $$x = -0.6, -2$$
- b) $$x = 2$$
- 13) $$x = \frac{8 + 4\sqrt{14}}{5}$$