To evaluate the expression \( xy - y \) for \( x = 9 \) and \( y = 4.8 \), we can substitute the values of \( x \) and \( y \) into the expression.
First, calculate \( xy \): \[ xy = 9 \times 4.8 = 43.2 \]
Next, subtract \( y \) from \( xy \): \[ xy - y = 43.2 - 4.8 = 38.4 \]
Therefore, the value of the expression \( xy - y \) is \( \boxed{38.4} \).