Question

Which represents all the values of x that make the rational expression 2x-4 over x-5 undefined?

x = 2

x = 5

x = –5 or x = –2

x = 2 or x = 5

Answer 1

x=5 because the denominator can never equal zero or it will be undefined. and 5-5=0

Answer 2

x = 5

Explanation:

The given rational expression is

`(2x-4)/(x-5)`

We need to find all the values of x that make the rational expression undefined.

The given expression is undefined if the value of denominator is equal to 0.

Equate the denominator equal to 0.

`x-5=0`

Add 5 on both sides.

`x-5+5=0+5`

`x=5`

It means the given expression is undefined for x=5. Therefore, the correct option is 2.