Rational Equations 684Bda
1. **State the problem:** Solve the rational equation $$1 + \frac{2}{x+1} = \frac{3x+7}{x^2 + 10x + 9}$$ for all values of $x$.
2. **Identify the denominators and restrictions:** The denominators are $x+1$ and $x^2 + 10x + 9$. Factor the quadratic denominator:
$$x^2 + 10x + 9 = (x+1)(x+9)$$
Restrictions: $x \neq -1$ and $x \neq -9$ because these values make denominators zero.
3. **Rewrite the equation with factored denominators:**
$$1 + \frac{2}{x+1} = \frac{3x+7}{(x+1)(x+9)}$$
4. **Multiply both sides by the common denominator $(x+1)(x+9)$ to clear fractions:**
$$ (x+1)(x+9) \cdot 1 + (x+1)(x+9) \cdot \frac{2}{x+1} = (x+1)(x+9) \cdot \frac{3x+7}{(x+1)(x+9)} $$
Simplify each term:
- First term: $(x+1)(x+9)$
- Second term: $(x+9) \cdot 2 = 2(x+9)$
- Third term: $3x+7$
So the equation becomes:
$$ (x+1)(x+9) + 2(x+9) = 3x + 7 $$
5. **Expand and simplify:**
- Expand $(x+1)(x+9) = x^2 + 10x + 9$
- Expand $2(x+9) = 2x + 18$
So:
$$ x^2 + 10x + 9 + 2x + 18 = 3x + 7 $$
Combine like terms on the left:
$$ x^2 + 12x + 27 = 3x + 7 $$
6. **Bring all terms to one side to form a quadratic equation:**
$$ x^2 + 12x + 27 - 3x - 7 = 0 $$
$$ x^2 + 9x + 20 = 0 $$
7. **Factor the quadratic:**
$$ x^2 + 9x + 20 = (x + 4)(x + 5) = 0 $$
8. **Solve for $x$:**
$$ x + 4 = 0 \Rightarrow x = -4 $$
$$ x + 5 = 0 \Rightarrow x = -5 $$
9. **Check restrictions:** Recall $x \neq -1$ and $x \neq -9$. Both $-4$ and $-5$ are allowed.
**Final answer:**
$$ \boxed{x = -4, -5} $$