1. Divide the first row by -4
(1, -5/4, -3/2)
2. Multiply the first row by -2
(-2, 5/2, 3)
3. Subtract the first row from the third row and restore it.
1 (1, -5/4, -3/2)
3 (0, -15/2, 1)
4. Restore the first row to the original view
(-4, 5, 6)
5. Divide the second row by 4
(0, 1, 1)
6. Multiply the second row by -15/2
(0, -15/2, -15/2)
7. Subtract the second row from the third row and restore it
2 (0, 1, 1)
3 (0, 0, 17/2)
8. Restore the second row to the original view
(0, 4, 4)
9. Multiply the main diagonal elements
-4 x 4 x 17/2 = 136
Answer: Δ = 136
