Question:
If $|A|$ denotes the value of the determinant of a square matrix of order 3, then $|-2 \mathrm{~A}|=$ ____________
Solution:
Given:
A is a 3 × 3 matrix
Now,
$|-2 A|=(-2)^{3}|A| \quad(\because$ Order of $A$ is $3 \times 3)$
$=-8|A|$
Hence, $|-2 A|=-8|\underline{A}|$.