How do you find the domain of y=2xx+9?

1 Answer
Oct 3, 2016

x9 or interval notation (,9)U(9,)

Explanation:

If a value of x results in y being "undefined", that value of x is not included in the domain. The domain is the allowed values of x.

For a rational equation like this example, dividing by zero will result in an undefined y. So, the denominator should not equal zero.

x+9a0
a9aa9

x9

A value of 9 will result in a zero in the denominator, so 9 is not be included in the domain.

In interval notation, this is written as (,9)U(9,)