Question

For what value of x is the rational expression below undefined x-4/4-x

Answer 1

Answer: -4

Explanation:

I answered none and got it wrong. Correct answer is -4

Answer 2

None.

Explanation:

The expression

`(x-4)/(4-x)`

can be rewritten as

`(x-4)/(-(x-4))` (multiplying the denominator by -1)

and then it simplifies to

`(x-4)/(-(x-4))=-1`

which is just a constant, and is the same for every value of
`x`; therefore, the expression is undefined nowhere.