Rational Equations 22Ca76
1. **State the problem:** Solve the rational equation $$\frac{9}{x^2 - 6x + 9} = \frac{3x}{x^2 - 3x}$$ and state any restrictions on $x$.
2. **Identify restrictions:** The denominators cannot be zero.
- For $x^2 - 6x + 9 = (x-3)^2$, so $x \neq 3$.
- For $x^2 - 3x = x(x-3)$, so $x \neq 0$ and $x \neq 3$.
3. **Rewrite the equation:**
$$\frac{9}{(x-3)^2} = \frac{3x}{x(x-3)}$$
Simplify the right side denominator:
$$\frac{3x}{x(x-3)} = \frac{3x}{x(x-3)}$$ (no simplification yet).
4. **Cross-multiply:**
$$9 \cdot x(x-3) = 3x \cdot (x-3)^2$$
5. **Expand both sides:**
Left: $$9x(x-3) = 9x^2 - 27x$$
Right: $$3x(x-3)^2 = 3x(x^2 - 6x + 9) = 3x^3 - 18x^2 + 27x$$
6. **Set equation:**
$$9x^2 - 27x = 3x^3 - 18x^2 + 27x$$
7. **Bring all terms to one side:**
$$0 = 3x^3 - 18x^2 + 27x - 9x^2 + 27x$$
Simplify:
$$0 = 3x^3 - 27x^2 + 54x$$
8. **Factor out common terms:**
$$0 = 3x(x^2 - 9x + 18)$$
9. **Solve each factor:**
- $3x = 0 \Rightarrow x = 0$ (excluded from restrictions)
- Solve quadratic $x^2 - 9x + 18 = 0$
10. **Quadratic formula:**
$$x = \frac{9 \pm \sqrt{81 - 72}}{2} = \frac{9 \pm \sqrt{9}}{2} = \frac{9 \pm 3}{2}$$
11. **Solutions:**
- $x = \frac{9 + 3}{2} = 6$
- $x = \frac{9 - 3}{2} = 3$ (excluded from restrictions)
12. **Final valid solution:**
$$x = 6$$
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1. **State the problem:** Solve the rational equation $$\frac{1}{x^2} + \frac{x+3}{2x} = \frac{1}{2}$$ and state any restrictions on $x$.
2. **Identify restrictions:**
- $x^2 \neq 0 \Rightarrow x \neq 0$
- $2x \neq 0 \Rightarrow x \neq 0$
3. **Find common denominator:**
The common denominator is $2x^2$.
4. **Rewrite each term with common denominator:**
$$\frac{1}{x^2} = \frac{2}{2x^2}$$
$$\frac{x+3}{2x} = \frac{(x+3)x}{2x^2} = \frac{x^2 + 3x}{2x^2}$$
$$\frac{1}{2} = \frac{x^2}{2x^2}$$
5. **Rewrite equation:**
$$\frac{2}{2x^2} + \frac{x^2 + 3x}{2x^2} = \frac{x^2}{2x^2}$$
6. **Combine left side:**
$$\frac{2 + x^2 + 3x}{2x^2} = \frac{x^2}{2x^2}$$
7. **Cross-multiply:**
$$2 + x^2 + 3x = x^2$$
8. **Simplify:**
$$2 + 3x = 0$$
9. **Solve for $x$:**
$$3x = -2 \Rightarrow x = -\frac{2}{3}$$
10. **Check restrictions:**
$x = -\frac{2}{3} \neq 0$, so valid.
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**Final answers:**
- For the first equation: $x = 6$
- For the second equation: $x = -\frac{2}{3}$
**Restrictions:**
- $x \neq 0, 3$ for the first equation
- $x \neq 0$ for the second equation