1. **State the problem:** Find the limit $$\lim_{x \to -1} \frac{x^3 + 4x^2 + 5x + 2}{2x^2 + 3x + 1}$$.
2. **Check direct substitution:** Substitute $x = -1$ into numerator and denominator.
Numerator: $$(-1)^3 + 4(-1)^2 + 5(-1) + 2 = -1 + 4 - 5 + 2 = 0$$
Denominator: $$2(-1)^2 + 3(-1) + 1 = 2 - 3 + 1 = 0$$
Since direct substitution gives $\frac{0}{0}$, an indeterminate form, we need to simplify.
3. **Factor numerator and denominator:**
Numerator: $x^3 + 4x^2 + 5x + 2$
Try factoring by grouping:
$$x^3 + 4x^2 + 5x + 2 = (x^3 + 4x^2) + (5x + 2) = x^2(x + 4) + 1(5x + 2)$$
This does not factor nicely by grouping, so try rational root theorem.
Test $x = -1$:
$$(-1)^3 + 4(-1)^2 + 5(-1) + 2 = 0$$
So $(x + 1)$ is a factor.
Divide numerator by $(x + 1)$:
Using synthetic division:
Coefficients: 1 | 4 | 5 | 2
-1 | -1 | -3 | -2
Sum: 1 | 3 | 2 | 0
So numerator factors as:
$$ (x + 1)(x^2 + 3x + 2) $$
Further factor $x^2 + 3x + 2$:
$$x^2 + 3x + 2 = (x + 1)(x + 2)$$
So numerator:
$$ (x + 1)^2 (x + 2) $$
Denominator: $2x^2 + 3x + 1$
Factor:
$$2x^2 + 3x + 1 = (2x + 1)(x + 1)$$
4. **Simplify the fraction:**
$$\frac{(x + 1)^2 (x + 2)}{(2x + 1)(x + 1)} = \frac{\cancel{(x + 1)} (x + 1)(x + 2)}{(2x + 1) \cancel{(x + 1)}} = \frac{(x + 1)(x + 2)}{2x + 1}$$
5. **Evaluate the limit by direct substitution now:**
$$\lim_{x \to -1} \frac{(x + 1)(x + 2)}{2x + 1} = \frac{(-1 + 1)(-1 + 2)}{2(-1) + 1} = \frac{0 \times 1}{-2 + 1} = \frac{0}{-1} = 0$$
**Final answer:**
$$\boxed{0}$$
Limit Rational Function B7Ded2
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