MCQ
What must be the matrix $X$ if $2X + \left[ {\begin{array}{*{20}{c}}1&2\\3&4\end{array}} \right] = \left[ {\begin{array}{*{20}{c}}3&8\\7&2\end{array}} \right]$
  • $\left[ {\begin{array}{*{20}{c}}1&3\\2&{ - 1}\end{array}} \right]$
  • B
    $\left[ {\begin{array}{*{20}{c}}1&{ - 3}\\2&{ - 1}\end{array}} \right]$
  • C
    $\left[ {\begin{array}{*{20}{c}}2&6\\4&{ - 2}\end{array}} \right]$
  • D
    $\left[ {\begin{array}{*{20}{c}}2&{ - 6}\\4&{ - 2}\end{array}} \right]$

Answer

Correct option: A.
$\left[ {\begin{array}{*{20}{c}}1&3\\2&{ - 1}\end{array}} \right]$
a
(a) $2X\, = \left[ {\begin{array}{*{20}{c}}3&8\\7&2\end{array}} \right] - \left[ {\begin{array}{*{20}{c}}1&2\\3&4\end{array}} \right]$
$2X = \left[ {\begin{array}{*{20}{c}}2&6\\4&{ - 2}\end{array}} \right] \Rightarrow X = \left[ {\begin{array}{*{20}{c}}1&3\\2&{ - 1}\end{array}} \right]$.

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