Question

$A=\left[\begin{array}{cc}1& 0\\ 4& 1\end{array}\right]$ , det $\left(4A^{-1}\right)$

• A. $16$
• B. $8$
• C. $4$
• D. $1$

Answer 1

The correct option is A $16$

$\text{det}\left(A\right)=1\times 1-4\times 0=1$
Also order of matrix is $2$
Thus $\text{det}\left(4A^{-1}\right)=4^{2}det\left(A^{-1}\right)=16\times 1=16$