TS EAMCET · Maths · Determinants
In the matrix \(\left[\begin{array}{ccc}-1 & x & 3 \\ -4 & -5 & -6 \\ -7 & y & 9\end{array}\right]\), if the cofactors of -6 and -7 are respectively 22 and 27 , then \(5 x+y=\)
- A 0
- B -1
- C -2
- D -4
Answer & Solution
Correct Answer
(C) -2
Step-by-step Solution
Detailed explanation
\begin{aligned} & \text { } \mathrm{A}=\left[\begin{array}{ccc}-1 & \mathrm{x} & 3 \\ -4 & -5 & -6 \\ -7 & \mathrm{y} & 9\end{array}\right] \\ & \text { Here } \mathrm{A}_{23}=(-1)^{2+3}[-\mathrm{y}+7 \mathrm{x}]=(-1)(7 \mathrm{x}-\mathrm{y})=-7 \mathrm{x}+\mathrm{y} \\ &…
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