A∣4,−2,9∣A|4,-2,9|A∣4,−2,9∣
∣4812−1−2−3369∣\left|\begin{array}{ccc}4 & 8 & 12 \\-1 & -2 & -3 \\3 & 6 & 9\end{array}\right|4−138−2612−39
∣4−20∣\left|\begin{array}{c}4 \\-2 \\0\end{array}\right|4−20
∣11∣|11|∣11∣