MCQ
The inverse of the matrix $\left[ {\begin{array}{*{20}{c}}5&{ - 2}\\3&1\end{array}} \right]$ is
  • $\frac{1}{{11}}\left[ {\begin{array}{*{20}{c}}1&2\\{ - 3}&5\end{array}} \right]$
  • B
    $\left[ {\begin{array}{*{20}{c}}1&2\\{ - 3}&5\end{array}} \right]$
  • C
    $\frac{1}{{13}}\left[ {\begin{array}{*{20}{c}}{ - 2}&5\\1&3\end{array}} \right]$
  • D
    $\left[ {\begin{array}{*{20}{c}}1&3\\{ - 2}&5\end{array}} \right]$

Answer

Correct option: A.
$\frac{1}{{11}}\left[ {\begin{array}{*{20}{c}}1&2\\{ - 3}&5\end{array}} \right]$
a
(a) $A = \left[ {\begin{array}{*{20}{c}}5&{ - 2}\\3&1\end{array}} \right]$

$|A|\, = 11,{A_{11}} = 1,{A_{12}} = - 3,{A_{21}} = 2,{A_{22}} = 5$

${A^{ - 1}} = \frac{1}{{11}}\left[ {\begin{array}{*{20}{c}}1&2\\{ - 3}&5\end{array}} \right]$.

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