Question

Which of the following values of x makes the rational expression below undefined? x-25/x+13

Answer 1

X-25 / x + 13
 For this case what you should know is that an indefinite expression are those in which mathematically no numerical value can be obtained.
 We have then that a division between zero causes an expression to be undefined.
 For x = -13 we have:
 (-13-25) / (- 13 + 13) = - 38/0 (undefined)
 Answer:
 x = -13
 d. -13

Answer 2

Answer:

Option D

Step-by-step explanation:

We will check each option for the given expression (x-25)/(x+13)

(A). for x = 13

$(\frac{x-25}{x+13})=\frac{13-25}{13+13} =\frac{-12}{26}$

So expression is defined.

(B). for x = 0

$\frac{x-25}{x+13}=\frac{0-25}{0+13} =(\frac{-25}{13})$

So expression is defined.

(C). For x = 25

$(\frac{x-25}{x+13})=\frac{25-25}{25+13} =0$

So expression is defined

(D). For x = -13

$\frac{x-25}{x+13}=\frac{-13-25}{-13+13}=( \frac{-38}{0})$

Function is not defined.

Option D is the answer.