M = [34621−1−135]\begin{bmatrix}3 & 4 & 6\\2 & 1 & -1\\-1 & 3 & 5\end{bmatrix}32−14136−15
|M| = 3[1−135]\begin{bmatrix}1 & -1\\3 & 5\end{bmatrix}[13−15] - 4[2−1−15]\begin{bmatrix}2 & -1\\-1 & 5\end{bmatrix}[2−1−15] + 6[21−13]\begin{bmatrix}2 & 1\\-1 & 3\end{bmatrix}[2−113]
3(5 + 3) - 4(10 - 1) + 6(6 + 1) = 24 - 36 + 42 = 30
