Answer:
See below for the matrix
D = 100
Explanation:
![\left[\begin{array}{cccc}3&2&1&-8\\-1&-2&4&7\\1&-6&-3&15\end{array}\right]](https://img.qammunity.org/2022/formulas/mathematics/high-school/vpf4xfyp0e8qcrrc1k9wo5g7usf7mmjaea.png)
3 2 1
D = -1 -2 4 = 3(-2)(-3) + 2(4)(1) + 1(-1)(-6)
1 -6 -3
- 1(-2)(1) - 3(4)(-6) - 2(-1)(-3)
= 18 + 8 + 6 + 2 + 72 - 6
= 100
Sorry, I can't type the vertical bars.
I hope this is what you are looking for.