1. **State the problem:** Simplify the complex fraction $$\frac{\frac{x^2 - 1}{x^2 + x}}{\frac{x - 1}{x + 1}}$$ and find which expression it is equivalent to.
2. **Recall the rule for dividing fractions:** Dividing by a fraction is the same as multiplying by its reciprocal. So,
$$\frac{\frac{x^2 - 1}{x^2 + x}}{\frac{x - 1}{x + 1}} = \frac{x^2 - 1}{x^2 + x} \times \frac{x + 1}{x - 1}$$
3. **Factor all polynomials where possible:**
- $x^2 - 1$ is a difference of squares: $$x^2 - 1 = (x - 1)(x + 1)$$
- $x^2 + x$ can be factored by taking out $x$: $$x^2 + x = x(x + 1)$$
4. **Rewrite the expression with factored forms:**
$$\frac{(x - 1)(x + 1)}{x(x + 1)} \times \frac{x + 1}{x - 1}$$
5. **Multiply the fractions:**
$$\frac{(x - 1)(x + 1)}{x(x + 1)} \times \frac{x + 1}{x - 1} = \frac{(x - 1)(x + 1)(x + 1)}{x(x + 1)(x - 1)}$$
6. **Cancel common factors:**
- Cancel $(x - 1)$ in numerator and denominator:
$$\frac{\cancel{(x - 1)}(x + 1)(x + 1)}{x(x + 1)\cancel{(x - 1)}}$$
- Cancel one $(x + 1)$ in numerator and denominator:
$$\frac{(x + 1)\cancel{(x + 1)}}{x\cancel{(x + 1)}} = \frac{x + 1}{x}$$
7. **Final simplified expression:**
$$\frac{x + 1}{x}$$
8. **Compare with given options:** None of the options directly match $$\frac{x + 1}{x}$$, so let's check if any option simplifies to this.
- Option A: $$-3\frac{x - 1}{x + 3}$$ no.
- Option B: $$3(x - 1)$$ no.
- Option C: $$3x(x - 1)$$ no.
- Option D: $$-\frac{x + 3}{x - 1}$$ no.
Therefore, none of the options match the simplified expression $$\frac{x + 1}{x}$$.
**Note:** The problem asks which expression is equivalent to the quotient, but none of the options match the simplified form. The simplified form is $$\frac{x + 1}{x}$$.
Complex Fraction 343D94
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