1. **State the problem:** Find the limit \( \lim_{x \to 3} \frac{x^2 - 9}{x - 3} \).
2. **Recall the formula and rules:** The limit of a rational function as \( x \) approaches a value can often be found by simplifying the expression, especially if direct substitution leads to an indeterminate form like \( \frac{0}{0} \).
3. **Evaluate the expression directly:** Substitute \( x = 3 \) into the numerator and denominator:
$$\frac{3^2 - 9}{3 - 3} = \frac{9 - 9}{0} = \frac{0}{0}$$
This is an indeterminate form, so we need to simplify.
4. **Factor the numerator:**
$$x^2 - 9 = (x - 3)(x + 3)$$
5. **Rewrite the expression:**
$$\frac{(x - 3)(x + 3)}{x - 3}$$
6. **Cancel the common factor \( x - 3 \):**
$$\frac{\cancel{(x - 3)}(x + 3)}{\cancel{x - 3}} = x + 3$$
7. **Evaluate the simplified expression at \( x = 3 \):**
$$3 + 3 = 6$$
**Final answer:**
$$\lim_{x \to 3} \frac{x^2 - 9}{x - 3} = 6$$
Limit Rational 65Fc99
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