CUET Preparation Today
CUET
-- Mathematics - Section B1
Matrices
If A and B are square matrices of order 3 such that $|A|=-1, |B|=3 $ then $3AB$ is :
-9
-81
-27
81
The correct answer is Option (2) → -81
$|3AB|=3^3|A||B|$
$=3^3(-1)(3)=-81$
