MHT CET · Maths · Determinants
If \(A=\left[a_{i j}\right]_{3 \times 3}=\left[\begin{array}{ccc}1 & 3 & 3 \\ -1 & 2 & 2 \\ 1 & 1 & 4\end{array}\right]\) and \(A_{i j}\) is a cofactor of \(a_{i j}\) then the value of \(a_{31} A_{31}+a_{32} A_{32}+a_{33} A_{33}\) is equal to
- A 5
- B 15
- C 20
- D 0
Answer & Solution
Correct Answer
(B) 15
Step-by-step Solution
Detailed explanation
\(a_{31} A_{31}+a_{32} A_{32}+a_{33} A_{33}=|A|\)
\(=1 \times(8-2)-3(-4-2)+3(-1-2)=6+18-9=15\)
\(=1 \times(8-2)-3(-4-2)+3(-1-2)=6+18-9=15\)
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