1. **State the problem:** Simplify the expression $$\frac{x^{2} - 16}{x^{2} - 8x + 16} - \frac{x^{2}}{x^{2} + 4x} = \lambda$$ and express it in simplest form.
2. **Factor all polynomials:**
- Numerator of first fraction: $$x^{2} - 16 = (x - 4)(x + 4)$$
- Denominator of first fraction: $$x^{2} - 8x + 16 = (x - 4)^{2}$$
- Numerator of second fraction: $$x^{2}$$ (already factored as $$x \cdot x$$)
- Denominator of second fraction: $$x^{2} + 4x = x(x + 4)$$
3. **Rewrite the expression with factored forms:**
$$\frac{(x - 4)(x + 4)}{(x - 4)^{2}} - \frac{x^{2}}{x(x + 4)}$$
4. **Simplify each fraction where possible:**
- First fraction: cancel one $$x - 4$$ term:
$$\frac{(x - 4)(x + 4)}{(x - 4)^{2}} = \frac{x + 4}{x - 4}$$
- Second fraction: simplify numerator and denominator:
$$\frac{x^{2}}{x(x + 4)} = \frac{x}{x + 4}$$
5. **Rewrite the expression:**
$$\frac{x + 4}{x - 4} - \frac{x}{x + 4}$$
6. **Find common denominator:**
The common denominator is $$(x - 4)(x + 4)$$.
7. **Rewrite each fraction with common denominator:**
$$\frac{(x + 4)^{2}}{(x - 4)(x + 4)} - \frac{x(x - 4)}{(x + 4)(x - 4)}$$
8. **Combine the fractions:**
$$\frac{(x + 4)^{2} - x(x - 4)}{(x - 4)(x + 4)}$$
9. **Expand the numerators:**
- $$(x + 4)^{2} = x^{2} + 8x + 16$$
- $$x(x - 4) = x^{2} - 4x$$
10. **Subtract the numerators:**
$$x^{2} + 8x + 16 - (x^{2} - 4x) = x^{2} + 8x + 16 - x^{2} + 4x = 12x + 16$$
11. **Simplify numerator:**
$$12x + 16 = 4(3x + 4)$$
12. **Rewrite the expression:**
$$\frac{4(3x + 4)}{(x - 4)(x + 4)}$$
13. **Final simplified form:**
$$\lambda = \frac{4(3x + 4)}{x^{2} - 16}$$
**Answer:** $$\boxed{\lambda = \frac{4(3x + 4)}{x^{2} - 16}}$$
Simplify Fractions 79C1F5
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