See Explanation
Step-by-step explanation:
[tex] \begin{bmatrix} 1 & 2 \\ 3 & 4 \end{bmatrix} \\ \\ = 4 \times 1 - 3 \times 2 \\ \\ = 4 - 6 \\ \\ = - 2[/tex]
[tex] \begin{bmatrix} 4 & 2 & 6 \\ - 1 & - 4 & 5\\ 3 & 7 & 2 \end{bmatrix} \\ \\
=4(-4\times 2-5\times 7)\\ -2(-1\times 2-5\times 3)\\ +6(-1\times 7-(-4)\times 3)\\\\
= 4(-8-35) -2(-2-15) \\+6(-7+12)\\\\
= 4(-43) -2(-17) +6(5)\\\\
= - 172 + 34 + 30\\\\
= 64 - 172\\\\
= - 108 \\[/tex]
