Choose the one alternative that best completes the statement or answers the question.
Find all real numbers excluded from the domain of the function. Then give the domain, using set builder notation.
-$f(x)=\frac{x^{2}-5 x}{x^{2}-4 x-45}$
A) $-9,5 ;\{x \mid x \neq-9,5\}$
B) $-5,9 ;\{x \mid x \neq-5,9\}$
C) $-5,5 ;\{x \mid x \neq-5,5\}$
D) 0,$5 ;\{x \mid x \neq 0,5\}$

Question

Quizplus · Accepted Answer

To find the excluded values, set the denominator equal to zero and solve for x: $x^2 - 4x - 45 = 0$. Factoring or using the quadratic formula gives $x = -5$ and $x = 9$ as the roots. These values are excluded from the domain, so the domain is $\{x \mid x \neq -5, 9\}$.

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