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Determinants — Maths STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceMathsDeterminants2 Marks
Question
Using cofactors of elements of second row, evaluate $\Delta = \left| {\begin{array}{*{20}{c}} 5&3&8 \\ 2&0&1 \\ 1&2&3 \end{array}} \right|$
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Answer

$\Delta = {a_{21}}{A_{21}} + {a_{22}}{A_{22}} + {a_{23}}{A_{23}}$
$ = - 2\left( {9 - 16} \right) + 0\left( {15 - 8} \right) - 1\left( {10 - 3} \right)$
$ = 14 + 0 - 7$
= 7.
Which is the required solution.

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