Questions: 21945, Fall 2024 Rational Expressions and Dividing Question 19, 6.1.141 Determine whether the following statement is true or false. If the statement is false, make the necessary change. The domain of f(x) = 5/(x(x-6)+8(x-6)) is (-∞, 6) ∪ (6, ∞). Select the correct choice below and, if necessary, fill in the answer box to complete your choice A. The statement is false. The domain of f(x) is (Type your answer in interval notation.) B. The statement is true.

21945, Fall 2024

Rational Expressions and Dividing Question 19, 6.1.141

Determine whether the following statement is true or false. If the statement is false, make the necessary change. The domain of f(x) = 5/(x(x-6)+8(x-6)) is (-∞, 6) ∪ (6, ∞).

Select the correct choice below and, if necessary, fill in the answer box to complete your choice A. The statement is false. The domain of f(x) is  (Type your answer in interval notation.) B. The statement is true.
Transcript text: 21945, Fall 2024 Rational Expressions and Dividing Question 19, 6.1.141 Determine whether the following statement is true or false. If the statement is false, make the necessary cha The domain of $f(x)=\frac{5}{x(x-6)+8(x-6)}$ is $(-\infty, 6) \cup(6, \infty)$. Select the correct choice below and, if necessary, fill in the answer box to complete your choice A. The statement is false. The domain of $f(x)$ is $\square$ (Type your answer in interval notation.) B. The statement is true.
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Solution

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Solution Steps

Solution Approach
  1. Simplify the given rational expression \( f(x) = \frac{5}{x(x-6) + 8(x-6)} \).
  2. Combine like terms in the denominator.
  3. Identify the values of \( x \) that make the denominator zero, as these values are excluded from the domain.
  4. Determine the domain of \( f(x) \) by excluding these values from the set of all real numbers.
Step 1: Simplify the Expression

We start with the function \( f(x) = \frac{5}{x(x-6) + 8(x-6)} \). First, we simplify the denominator:

\[ x(x-6) + 8(x-6) = x^2 - 6x + 8x - 48 = x^2 + 2x - 48 \]

Step 2: Find Excluded Values

Next, we need to find the values of \( x \) that make the denominator zero. We solve the equation:

\[ x^2 + 2x - 48 = 0 \]

Using the quadratic formula \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), where \( a = 1, b = 2, c = -48 \):

\[ x = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 1 \cdot (-48)}}{2 \cdot 1} = \frac{-2 \pm \sqrt{4 + 192}}{2} = \frac{-2 \pm \sqrt{196}}{2} = \frac{-2 \pm 14}{2} \]

This gives us the solutions:

\[ x = \frac{12}{2} = 6 \quad \text{and} \quad x = \frac{-16}{2} = -8 \]

Step 3: Determine the Domain

The values \( x = 6 \) and \( x = -8 \) make the denominator zero, so these values are excluded from the domain. Therefore, the domain of \( f(x) \) is:

\[ (-\infty, -8) \cup (-8, 6) \cup (6, \infty) \]

Final Answer

The statement that the domain of \( f(x) \) is \( (-\infty, 6) \cup (6, \infty) \) is false. The correct domain is:

\[ \boxed{(-\infty, -8) \cup (-8, 6) \cup (6, \infty)} \]

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