1. **State the problem:** Simplify the expression
$$\frac{2b - 5}{b^2 - 2b - 15} + \frac{3b}{b^2 + b - 30} \times \frac{b^2 + 8b + 12}{b + 3}$$
2. **Factor all polynomials:**
- Factor denominator $b^2 - 2b - 15$:
$$b^2 - 2b - 15 = (b - 5)(b + 3)$$
- Factor denominator $b^2 + b - 30$:
$$b^2 + b - 30 = (b + 6)(b - 5)$$
- Factor numerator $b^2 + 8b + 12$:
$$b^2 + 8b + 12 = (b + 6)(b + 2)$$
3. **Rewrite the expression with factored forms:**
$$\frac{2b - 5}{(b - 5)(b + 3)} + \frac{3b}{(b + 6)(b - 5)} \times \frac{(b + 6)(b + 2)}{b + 3}$$
4. **Simplify the multiplication part:**
$$\frac{3b}{(b + 6)(b - 5)} \times \frac{(b + 6)(b + 2)}{b + 3} = \frac{3b \cancel{(b + 6)} (b + 2)}{\cancel{(b + 6)} (b - 5)(b + 3)} = \frac{3b (b + 2)}{(b - 5)(b + 3)}$$
5. **Rewrite the entire expression:**
$$\frac{2b - 5}{(b - 5)(b + 3)} + \frac{3b (b + 2)}{(b - 5)(b + 3)}$$
6. **Combine the fractions since they have the same denominator:**
$$\frac{2b - 5 + 3b (b + 2)}{(b - 5)(b + 3)}$$
7. **Expand the numerator:**
$$3b (b + 2) = 3b^2 + 6b$$
So numerator becomes:
$$2b - 5 + 3b^2 + 6b = 3b^2 + 8b - 5$$
8. **Final expression:**
$$\frac{3b^2 + 8b - 5}{(b - 5)(b + 3)}$$
9. **Check if numerator factors:**
Discriminant $\Delta = 8^2 - 4 \times 3 \times (-5) = 64 + 60 = 124$ which is not a perfect square, so numerator does not factor nicely.
**Answer:**
$$\boxed{\frac{3b^2 + 8b - 5}{(b - 5)(b + 3)}}$$
Rational Expression F 88D687
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