To evaluate the expression \( tuv \) for \( t = -9 \), \( u = 0 \), and \( v = -23 \), we substitute the values into the expression:
\[ tuv = (-9) \cdot 0 \cdot (-23) \]
Since any number multiplied by 0 is 0, we have:
\[ tuv = 0 \]
Thus, the value of the expression \( tuv \) is \( 0 \).