In Exercises 15-22, evaluate the determinant, given that
\[
\left|\begin{array}{lll}
a & b & c \\
d & e & f \\
g & h & i
\end{array}\right|=-6
\]
15. \( \left|\begin{array}{lll}d & e & f \\ g & h & i \\ a & b & c\end{array}\right| \)
16. \( \left|\begin{array}{lll}g & h & i \\ d & e & f \\ a & b & c\end{array}\right| \)
17. \( \left|\begin{array}{rrr}3 a & 3 b & 3 c \\ -d & -e & -f \\ 4 g & 4 h & 4 i\end{array}\right| \)
18. \( \left|\begin{array}{ccc}a+d & b+e & c+f \\ -d & -e & -f \\ g & h & i\end{array}\right| \)
19. \( \left|\begin{array}{ccc}a+g & b+h & c+i \\ d & e & f \\ g & h & i\end{array}\right| \)
20. \( \left|\begin{array}{ccc}a & b & c \\ 2 d & 2 e & 2 f \\ g+3 a & h+3 b & i+3 c\end{array}\right| \)
21. \( \left|\begin{array}{ccc}-3 a & -3 b & -3 c \\ d & e & f \\ g-4 d & h-4 e & i-4 f\end{array}\right| \)
22. \( \left|\begin{array}{ccc}a & b & c \\ d & e & f \\ 2 a & 2 b & 2 c\end{array}\right| \)