Q. If $A$ and $B$ are square matrices of order 3 such that $|A| = - 1,\ |B| = 3\ then\ |3AB|$ is equal to
A) $- 9$
B) $- 81$
C) $- 27$
D) 81
Explanation
(b)
Since, $|A| = - 1,\ |B| = 3$
$\therefore|AB| = |A||B| = - 3$
Now, $|3AB| = (3)^{3}( - 3) = - 81$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.