Questions: Evaluate the limit. Answer exactly.
lim x→-3 (x^2-9)/(x+3)=
Evaluate the limit. Answer exactly.
lim x→-3 (x^2-9)/(x+3)=
Solution
Solution Steps
To evaluate the limit \(\lim _{x \rightarrow-3} \frac{x^{2}-9}{x+3}\), we can simplify the expression by factoring the numerator. The expression \(x^2 - 9\) is a difference of squares and can be factored as \((x - 3)(x + 3)\). This allows us to cancel the common factor of \(x + 3\) in the numerator and the denominator, simplifying the expression. After simplification, we can directly substitute \(x = -3\) to find the limit.
Step 1: Factor the Numerator
We start with the limit expression:
\[
\lim _{x \rightarrow -3} \frac{x^{2}-9}{x+3}
\]
The numerator \(x^2 - 9\) can be factored as a difference of squares:
\[
x^2 - 9 = (x - 3)(x + 3)
\]
Thus, we can rewrite the limit as:
\[
\lim _{x \rightarrow -3} \frac{(x - 3)(x + 3)}{x + 3}
\]
Step 2: Simplify the Expression
Next, we can cancel the common factor \(x + 3\) in the numerator and the denominator, provided \(x \neq -3\):
\[
\lim _{x \rightarrow -3} (x - 3)
\]
Step 3: Evaluate the Limit
Now, we can directly substitute \(x = -3\) into the simplified expression:
\[
-3 - 3 = -6
\]