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Using elementary transformations, find the inverse of each of the matrices, if it exists
in Exercises 1 to 17.

    Q11.    \begin{bmatrix} 2 & -6\\ 1 & -2 \end{bmatrix}

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A=\begin{bmatrix} 2 & -6\\ 1 & -2 \end{bmatrix}

                A=IA

\Rightarrow          \begin{bmatrix} 2 & -6\\ 1 & -2 \end{bmatrix} = \begin{bmatrix}1&0\\0&1 \end{bmatrix}A

             R_1\rightarrow R_1-3R_1

\Rightarrow        \begin{bmatrix} -1 & 0\\ 1 & -2 \end{bmatrix} = \begin{bmatrix}1&-3\\0&1 \end{bmatrix}A

\Rightarrow          R_2\rightarrow R_2+R_1

\Rightarrow          \begin{bmatrix} -1 & 0\\ 0 & -2 \end{bmatrix} = \begin{bmatrix}1&-3\\1&-2 \end{bmatrix}A

                  R_1\rightarrow -R_1

 \Rightarrow          \begin{bmatrix} 1 & 0\\ 0 & -2 \end{bmatrix} = \begin{bmatrix}-1&3\\1&-2 \end{bmatrix}A

                R_2\rightarrow \frac{R_2}{-2}

 \Rightarrow          \begin{bmatrix} 1 & 0\\ 0 & 1 \end{bmatrix} = \begin{bmatrix}-1&3\\\frac{1}{-2}&1 \end{bmatrix}A

   thus the inverse of matrix A is

\therefore A^{-1}=\begin{bmatrix}-1&3\\\frac{1}{-2}&1 \end{bmatrix}.

Posted by

seema garhwal

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