If A = \(\begin{pmatrix}2&5 \\1 &3\end{pmatrix}\) then adj A = ?A.

1.	If A = \(\begin{pmatrix}2&5 \\1 &3\end{pmatrix}\) then adj A = ?A. \(\begin{pmatrix}3&-5 \\-1 &2\end{pmatrix}\)B.\(\begin{pmatrix}3&-1 \\-5 &2\end{pmatrix}\)C.\(\begin{pmatrix}-1&2 \\3 &-5\end{pmatrix}\)D. None of these
Answer» To find adj A we will first find the cofactor matrix C₁₁ = 3 C₁₂ = -1 C₂₁= -5 C₂₂ = 2 Cofactor matrix A = \(\begin{pmatrix}3&-1 \\-5 &2\end{pmatrix}\) Adj A = \(\begin{pmatrix}3&-1 \\-5 &2\end{pmatrix}\) = \(\begin{pmatrix}3&-5 \\-1 &2\end{pmatrix}\)

If A = \(\begin{pmatrix}2&5 \\1 &3\end{pmatrix}\) then adj A = ?A. \(\begin{pmatrix}3&-5 \\-1 &2\end{pmatrix}\)B.\(\begin{pmatrix}3&-1 \\-5 &2\end{pmatrix}\)C.\(\begin{pmatrix}-1&2 \\3 &-5\end{pmatrix}\)D. None of these

Answer»

To find adj A we will first find the cofactor matrix

C₁₁ = 3 C₁₂ = -1

C₂₁= -5 C₂₂ = 2

Cofactor matrix A = \(\begin{pmatrix}3&-1 \\-5 &2\end{pmatrix}\)

Adj A = \(\begin{pmatrix}3&-1 \\-5 &2\end{pmatrix}\)

= \(\begin{pmatrix}3&-5 \\-1 &2\end{pmatrix}\)