Question

If $A$ is a non-singular matrix of order $3\times 3$, then adj $\left(adjA\right)$ is equal to

• A. $\left|A\right|A$
• B. ${\left|A\right|}^{2}A$
• C. ${\left|A\right|}^{-1}A$
• D. none of these

Answer 1

The correct option is A $\left|A\right|A$

Given A is a matrix of order 3.
Now, $adj\left(adjA\right)=|A{|}^{n-2}A$
So, $adj\left(adjA\right)=|A{|}^{3-2}A=|A|A$