1. **State the problem:** Simplify the expression $$\frac{5}{x^2 - 5x - 14} \div \frac{5x + 25}{x^2 - 2x - 35}$$.
2. **Rewrite division as multiplication by reciprocal:**
$$\frac{5}{x^2 - 5x - 14} \times \frac{x^2 - 2x - 35}{5x + 25}$$
3. **Factor all polynomials:**
- Factor denominator $x^2 - 5x - 14$:
$$x^2 - 5x - 14 = (x - 7)(x + 2)$$
- Factor numerator $x^2 - 2x - 35$:
$$x^2 - 2x - 35 = (x - 7)(x + 5)$$
- Factor denominator $5x + 25$:
$$5x + 25 = 5(x + 5)$$
4. **Substitute factored forms:**
$$\frac{5}{(x - 7)(x + 2)} \times \frac{(x - 7)(x + 5)}{5(x + 5)}$$
5. **Multiply numerators and denominators:**
$$\frac{5 \times (x - 7)(x + 5)}{(x - 7)(x + 2) \times 5(x + 5)}$$
6. **Cancel common factors:**
$$\frac{\cancel{5} \times \cancel{(x - 7)} \times \cancel{(x + 5)}}{\cancel{(x - 7)} \times (x + 2) \times \cancel{5} \times \cancel{(x + 5)}} = \frac{1}{x + 2}$$
7. **Final simplified expression:**
$$\boxed{\frac{1}{x + 2}}$$
This means the original expression simplifies to $\frac{1}{x + 2}$, provided $x \neq 7, -5, -2$ to avoid division by zero.
Rational Expression Division 9B047D
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.