Evaluate.
-$$\left| \begin{array} { l l l }
2 & 0 & 0 \
7 & 4 & 2 \
5 & 4 & 8
\end{array} \right|$$
A) $- 48$
B) 80
C) 48
D) 53

Question

Evaluate.
-$$\left| \begin{array} { l l l } 
2 & 0 & 0 \
7 & 4 & 2 \
5 & 4 & 8
\end{array} \right|$$
A) $- 48$
B) 80
C) 48
D) 53

Quizplus · Accepted Answer

The determinant of a lower triangular matrix is the product of its diagonal elements. Here, the determinant is $2 \times 4 \times 8 = 64$. However, the matrix is not lower triangular, so we calculate using cofactor expansion along the first row: $2 \times (4 \times 8 - 2 \times 4) = 2 \times (32 - 8) = 2 \times 24 = 48$.

Evaluate - ∣200742548∣\left| \begin{array} { l l l } 2 & 0 & 0 \\7 & 4 & 2 \\5 & 4 & 8\end{array} \right|​275​044​028​​

Evaluate
- $\left| \begin{array} { l l l } 2 & 0 & 0 \\7 & 4 & 2 \\5 & 4 & 8\end{array} \right|$