Find all numbers that are not in the domain of the function. Then give the domain using set notation.
-$f(x)=\frac{2 x+22}{x^{2}-1}$

A) $1 ;\{x \mid x \neq 1\}$

B) none; $(\infty, \infty)$

C) $-1,1 ;\{x \mid x \neq-1,1\}$

D) $-11,-1,1 ;\{x \mid x \neq-11,-1,1\}$

Question

Find all numbers that are not in the domain of the function. Then give the domain using set notation.
-$f(x)=\frac{2 x+22}{x^{2}-1}$

A) $1 ;\{x \mid x \neq 1\}$

B) none; $(\infty, \infty)$

C) $-1,1 ;\{x \mid x \neq-1,1\}$

D) $-11,-1,1 ;\{x \mid x \neq-11,-1,1\}$

Quizplus · Accepted Answer

The domain of the function $f(x)=\frac{2x+22}{x^2-1}$ excludes values of $x$ that make the denominator equal to zero. Factoring the denominator gives $x^2-1=(x-1)(x+1)$, so the values of $x$ that are not in the domain are $x=1$ and $x=-1$, because these values make the denominator zero. Therefore, the domain is all real numbers except $x=1$ and $x=-1$, which is represented as $\{x \mid x \neq-1,1\}$.

Find All Numbers That Are Not in the Domain of the Function