ExamBro
ExamBro
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

  1. A 5
  2. B 15
  3. C 20
  4. D 0
Verified Solution

Answer & Solution

Correct Answer

(B) 15

Step-by-step Solution

Detailed explanation

\(a_{31} A_{31}+a_{32} A_{32}+a_{33} A_{33}=|A|\)
\(=1 \times(8-2)-3(-4-2)+3(-1-2)=6+18-9=15\)