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Determinants — Maths STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceMathsDeterminants1 Mark
MCQ
For matrix $A=\left[\begin{array}{cc}2 & 5 \\ -11 & 7\end{array}\right],(\operatorname{adj} A)^{\prime}$ is equal to
  • A
    $\left[\begin{array}{ll}-2 & -5 \\ 11 & -7\end{array}\right]$
  • B
    $\left[\begin{array}{cc}7 & 5 \\ 11 & 2\end{array}\right]$
  • C
    $\left[\begin{array}{cc}7 & 11 \\ -5 & 2\end{array}\right]$
  • D
    $\left[\begin{array}{cc}7 & -5 \\ 11 & 2\end{array}\right]$
✓

Answer

We know that, $(\operatorname{adj} A)^{\prime}=$ cofactor matrix of $A$
Here, cofactor matrix of $A=\left[\begin{array}{cc}7 & 11 \\ -5 & 2\end{array}\right]=(\operatorname{adj} A)^{\prime}$

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