If \(A = [a_{ij}] = \begin{bmatrix}2&-1\\-3&4\\1&2\end{bmatrix}\) and \(B = [b_{ij}] = \begin{bmatrix}2&3&-5\\1&4&9\\0&7&-2\end{bmatrix}\), then the value of \(a_{11}b_{11} + a_{22}b_{22}\) is
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 20
The element \(a_{ij}\) is in row i and column j.
\(a_{11} = 2,\ a_{22} = 4\)
\(b_{11} = 2,\ b_{22} = 4\)
Hence
\(a_{11}b_{11} + a_{22}b_{22} = 2(2) + 4(4)\)
\(= 4 + 16 = 20\)