What is the undefined value for 22=4+5x/9x−6

To find the undefined value for the equation \( 22 = \frac{4 + 5x}{9x - 6} \), we first need to identify when the denominator equals zero, as division by zero is undefined.

The denominator is \( 9x - 6 \). We set it equal to zero and solve for \( x \):

\[
9x - 6 = 0
\]
\[
9x = 6
\]
\[
x = \frac{6}{9}
\]
\[
x = \frac{2}{3}
\]

Thus, the undefined value is \( x = \frac{2}{3} \).

As requested, it is in reduced fraction form.

So, the final answer is:
\[
\text{The undefined value is } \frac{2}{3}.
\]