Question:
If $A$ is a $2 \times 2$ matrix such that $|A|=5$, then $|5 A|=$______
Given:
$A$ is a $2 \times 2$ matrix
$|A|=5$
Solution:
Now,
$|5 A|=5^{2}|A| \quad(\because$ Order of $A$ is $2 \times 2)$
$=25|A|$
$=25 \times 5 \quad(\because|A|=5)$
$=125$
Hence, $|5 A|=\underline{125}$.