Question

For what value of x would the expression below be undefined? 2x − 15 x + 9

Answer 1

Hey there!

I'm assuming your expression is actually
`(2x - 15)/(x + 9)`. If it's not, let me know and I'll be happy to help you out further.

If x were equal to –9, your expression would be undefined. If you solve it with this value plugged in for x, you will get the following:


`(2x - 15)/(x + 9)`


`(2(-9) - 15)/((-9) + 9)`


`(-18 - 15)/(0)`


`(-33)/(0)`


`error`

You can't divide anything by zero. This expression would be undefined if x were –9 since it makes the denominator zero. Therefore, x ≠ –9.

Hope this helped you out! :-)