If $A=\begin{bmatrix}1 & -1 & 2 \\-2 & 2 & -4\\0 & 2 & 9\end{bmatrix}$ then $A^{-1}$ is equal to.
Answer & explanation
Correct answer: option 2
The correct answer is option (2) → does not exist
In $A=\begin{bmatrix}1 & -1 & 2 \\-2 & 2 & -4\\0 & 2 & 9\end{bmatrix}$
$R_2=-2R_1$ (proportional)
$⇒|A|=0$
$⇒A^{-1}$ does not exist