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Which one of the following matrices is the inverse of the matrix \[\left[ {\begin{array}{*{20}{c}} 1&{ - 1} \\ 0&1 \end{array}} \right]?\]

A. \[\left[ {\begin{array}{*{20}{c}} 1&1 \\ { - 1}&1 \end{array}} \right]\]

B. \[\left[ {\begin{array}{*{20}{c}} 1&0 \\ 1&1 \end{array}} \right]\]

C. \[\left[ {\begin{array}{*{20}{c}} 1&1 \\ 0&1 \end{array}} \right]\]

D. \[\left[ {\begin{array}{*{20}{c}} { - 1}&1 \\ 0&{ - 1} \end{array}} \right]\]

Answer: Option C


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