1. **State the problem:** Simplify the expression $$\frac{x + 5}{x - 4} - \frac{8x + 13}{x^2 - 3x - 4}$$.
2. **Factor the denominator:** Notice that $$x^2 - 3x - 4$$ can be factored.
$$x^2 - 3x - 4 = (x - 4)(x + 1)$$.
3. **Rewrite the expression with factored denominator:**
$$\frac{x + 5}{x - 4} - \frac{8x + 13}{(x - 4)(x + 1)}$$.
4. **Find common denominator:** The common denominator is $$ (x - 4)(x + 1) $$.
5. **Rewrite the first fraction with the common denominator:**
$$\frac{x + 5}{x - 4} = \frac{(x + 5)(x + 1)}{(x - 4)(x + 1)}$$.
6. **Express the subtraction with common denominator:**
$$\frac{(x + 5)(x + 1)}{(x - 4)(x + 1)} - \frac{8x + 13}{(x - 4)(x + 1)} = \frac{(x + 5)(x + 1) - (8x + 13)}{(x - 4)(x + 1)}$$.
7. **Expand the numerator:**
$$(x + 5)(x + 1) = x^2 + x + 5x + 5 = x^2 + 6x + 5$$.
8. **Substitute and simplify numerator:**
$$x^2 + 6x + 5 - (8x + 13) = x^2 + 6x + 5 - 8x - 13 = x^2 - 2x - 8$$.
9. **Factor the numerator:**
$$x^2 - 2x - 8 = (x - 4)(x + 2)$$.
10. **Rewrite the expression:**
$$\frac{(x - 4)(x + 2)}{(x - 4)(x + 1)}$$.
11. **Cancel common factor:**
$$\frac{\cancel{(x - 4)}(x + 2)}{\cancel{(x - 4)}(x + 1)} = \frac{x + 2}{x + 1}$$.
**Final answer:** $$\frac{x + 2}{x + 1}$$.
**Note:** The simplification is valid for $$x \neq 4$$ and $$x \neq -1$$ because these values make the original denominators zero.
Simplify Rational A3A868
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