Question

For which rational expression is -2 an excluded value of x?

Answer 1

Answer:

The first choice, $\frac{x-3}{x^{2}-4 }$

Step-by-step explanation:

Excluded value means that the value of x will make the denominator 0.

(-2)² - 4 = ?

4 - 4 = 0.

Therefore, it's the first choice– $\frac{x-3}{x^{2}-4 }$

Answer 2

Answer:

$x^2-3/x^2-4$

Step-by-step explanation:

An excluded value of x for any rational function or expression is when you have any value of x that makes the value of the function undefined. Thus, these values ​​must be excluded from the domain of the function.

in order to know if a value is an excluded value you have to calculate it in the expression:

x=-2

$x^2-3/x^2-4$=$(-2)^2-3/(-2)^2-4$=$4-3/4-4$= function undefined (because denominator 0 is undefined)

$x-3/x^2+4$=$-2-3/(-2)^2+4$=$-5/8$=function defined

$x^2-4/x-3$=$(-2)^2-4/-2-3$=$0$=function defined

$x^2+4/x-3$=$(-2)^2+4/-2-3$=$8/-5$=function defined