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Determinants — MATHS STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceMATHSDeterminants1 Mark
Question
Write the cofactor of the element $a_{31}$ in
$
A=\left(\begin{array}{lll}
3 & 2 & 6 \\
5 & 0 & 7 \\
3 & 8 & 5
\end{array}\right).
$
✓

Answer

(b) : We have, $A=\left(\begin{array}{lll}3 & 2 & 6 \\ 5 & 0 & 7 \\ 3 & 8 & 5\end{array}\right)$
Cofactor of $a_{31}=(-1)^{3+1}\left|\begin{array}{ll}2 & 6 \\ 0 & 7\end{array}\right|=14$

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