To simplify the expression \( \frac{9}{11}z - \frac{4}{11}z \), you can combine the terms since they have the same denominator and are like terms:
First, you take the coefficient of z from both terms and subtract them:
\( \frac{9}{11} - \frac{4}{11} = \frac{9-4}{11} \)
Then you solve the subtraction in the numerator:
\( \frac{5}{11} \)
So the simplified expression is:
\( \frac{5}{11}z \)