Questions: Question 3 of 8, Step 3 of 3 4 / 12 Correct Consider the function f(x)= x^2+8x+22 if x<-4 2x+14 if x ≥ -4 Step 3 of 3: Find the limit as x approaches -4 of f(x).

Question 3 of 8, Step 3 of 3
4 / 12
Correct

Consider the function
f(x)=
x^2+8x+22 if x<-4
2x+14 if x ≥ -4

Step 3 of 3: Find the limit as x approaches -4 of f(x).
Transcript text: Question 3 of 8, Step 3 of 3 $4 / 12$ Correct Consider the function \[ f(x)=\left\{\begin{array}{ll} x^{2}+8 x+22 & \text { if } x<-4 \\ 2 x+14 & \text { if } x \geq-4 \end{array}\right. \] Step 3 of $3:$ Find $\lim _{x \rightarrow-4} f(x)$.
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Solution

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Solution Steps

To find the limit of the piecewise function \( f(x) \) as \( x \) approaches \(-4\), we need to evaluate the left-hand limit and the right-hand limit separately. If both limits are equal, then the limit exists and is equal to that common value.

  1. Evaluate the left-hand limit as \( x \) approaches \(-4\) from the left (\( x < -4 \)).
  2. Evaluate the right-hand limit as \( x \) approaches \(-4\) from the right (\( x \geq -4 \)).
  3. Compare the two limits. If they are equal, that is the limit of \( f(x) \) as \( x \) approaches \(-4\).
Step 1: Define the Function

The function \( f(x) \) is defined as follows: \[ f(x) = \begin{cases} x^2 + 8x + 22 & \text{if } x < -4 \\ 2x + 14 & \text{if } x \geq -4 \end{cases} \]

Step 2: Calculate the Left-Hand Limit

To find the left-hand limit as \( x \) approaches \(-4\), we use the first piece of the function: \[ \lim_{x \to -4^-} f(x) = (-4)^2 + 8(-4) + 22 = 16 - 32 + 22 = 6 \]

Step 3: Calculate the Right-Hand Limit

To find the right-hand limit as \( x \) approaches \(-4\), we use the second piece of the function: \[ \lim_{x \to -4^+} f(x) = 2(-4) + 14 = -8 + 14 = 6 \]

Step 4: Compare the Limits

Since both the left-hand limit and the right-hand limit are equal: \[ \lim_{x \to -4^-} f(x) = 6 \quad \text{and} \quad \lim_{x \to -4^+} f(x) = 6 \] we conclude that: \[ \lim_{x \to -4} f(x) = 6 \]

Final Answer

\(\boxed{6}\)

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