To simplify \( 6i \cdot (-4)i \), we can start by rewriting the expression as follows:
\[ 6i \cdot (-4)i = 6 \cdot (-4) \cdot i \cdot i \]
Now, we can simplify each part:
-
Calculate \( 6 \cdot (-4) \): \[ 6 \cdot (-4) = -24 \]
-
Calculate \( i \cdot i \): \[ i \cdot i = i^2 = -1 \]
Now substitute these values back into the expression:
\[ 6i \cdot (-4)i = -24 \cdot (-1) = 24 \]
Thus, the simplified result is:
\[ \boxed{24} \]