CUET Preparation Today
CUET
-- Mathematics - Section A
Determinants
Cofactor of $a_{12}$ in $A=\left[\begin{array}{ccc}1 & 2 & 3 \\ 4 & -5 & 6 \\ 0 & 1 & -1\end{array}\right]$ is:
5
4
-4
-5
The correct answer is Option (2) - 4
$C_{12}=(-1)^{1+2}\begin{vmatrix}4&6\\0&-1\end{vmatrix}$
$=4$
