Which of the following matrix is invertible? $A_{1}=\left[\begin{array}{ll}4 & 2 \ 2 & 1\end{array} ight]$ $A_{2}=\left[\begin{array}{ccc}-1 & -2 & 3 \ 4 & 5 & 7 \ 2 & 4 & -6\end{array} ight]$ $A_{3}=\left[\begin{array}{lll}1 & 0 & 0 \ 5 & 2 & 1 \ 7 & 2 & 1\end{array} ight]$…

Question

Which of the following matrix is invertible? $A_{1}=\left[\begin{array}{ll}4 & 2 \ 2 & 1\end{array}ight]$ $A_{2}=\left[\begin{array}{ccc}-1 & -2 & 3 \ 4 & 5 & 7 \ 2 & 4 & -6\end{array}ight]$ $A_{3}=\left[\begin{array}{lll}1 & 0 & 0 \ 5 & 2 & 1 \ 7 & 2 & 1\end{array}ight]$ $A_{4}=\left[\begin{array}{lll}1 & 0 & 1 \ 0 & 2 & 3 \ 1 & 2 & 1\end{array}ight]$

Aicharya · Accepted Answer

Any Matrix is said to be invertiable only if $|\mathrm{A}| 
eq 0$ Here $\left|A_{4}ight|=\left|\begin{array}{lll} 1 & 0 & 1 \ 0 & 2 & 3 \ 1 & 2 & 1 \end{array}ight| \quad=(-4)+1(-2)=-6 
eq 0$

Which of the following matrix is invertible? $A_{1}=\left[\begin{array}{ll}4 & 2 \\ 2 & 1\end{array}\right]$…

Solution