1. **State the problem:** Simplify the expression $$\frac{x+8}{x^2+9x+20} + \frac{x+5}{x^2+7x+12}$$ ignoring restrictions on the variable.
2. **Factor the denominators:**
$$x^2+9x+20 = (x+4)(x+5)$$
$$x^2+7x+12 = (x+3)(x+4)$$
3. **Rewrite the expression with factored denominators:**
$$\frac{x+8}{(x+4)(x+5)} + \frac{x+5}{(x+3)(x+4)}$$
4. **Find the common denominator:**
The least common denominator (LCD) is $$(x+3)(x+4)(x+5)$$
5. **Rewrite each fraction with the LCD:**
$$\frac{(x+8)(x+3)}{(x+3)(x+4)(x+5)} + \frac{(x+5)(x+5)}{(x+3)(x+4)(x+5)}$$
6. **Combine the numerators over the common denominator:**
$$\frac{(x+8)(x+3) + (x+5)^2}{(x+3)(x+4)(x+5)}$$
7. **Expand the numerators:**
$$(x+8)(x+3) = x^2 + 3x + 8x + 24 = x^2 + 11x + 24$$
$$(x+5)^2 = x^2 + 10x + 25$$
8. **Add the expanded numerators:**
$$x^2 + 11x + 24 + x^2 + 10x + 25 = 2x^2 + 21x + 49$$
9. **Rewrite the expression:**
$$\frac{2x^2 + 21x + 49}{(x+3)(x+4)(x+5)}$$
10. **Check if numerator factors:**
Try to factor $2x^2 + 21x + 49$.
Calculate discriminant:
$$\Delta = 21^2 - 4 \times 2 \times 49 = 441 - 392 = 49$$
Since $\Delta$ is a perfect square, factorization is possible:
$$2x^2 + 21x + 49 = (2x + 7)(x + 7)$$
11. **Final simplified expression:**
$$\frac{(2x + 7)(x + 7)}{(x+3)(x+4)(x+5)}$$
**Answer:** $$\boxed{\frac{(2x + 7)(x + 7)}{(x+3)(x+4)(x+5)}}$$
Simplify Rational Expression C29039
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