Find all values of the variable for which the rational expression is undefined.
-$$\frac { x ^ { 2 } - 6 x - 16 } { x ^ { 2 } - 81 }$$
A) $- 8,2$
B) $- 8$
C) $- 2,8$
D) $- 9,9$

Question

Quizplus · Accepted Answer

A rational expression is undefined when its denominator is equal to zero. The denominator of the given expression is $x^2 - 81$, which can be factored into $(x - 9)(x + 9)$. Setting each factor equal to zero gives the values of $x$ for which the expression is undefined: $x - 9 = 0$ leads to $x = 9$, and $x + 9 = 0$ leads to $x = -9$.

Find All Values of the Variable for Which the Rational x2−6x−16x2−81\frac { x ^ { 2 } - 6 x - 16 } { x ^ { 2 } - 81 }x2−81x2−6x−16​

Find All Values of the Variable for Which the Rational $\frac { x ^ { 2 } - 6 x - 16 } { x ^ { 2 } - 81 }$