Mathematics 10 — Exercise Review · Q4 (ii)

Full question

Find Adj B.

A = [\begin{matrix} 7 & 3 \\ 2 & 1 \end{matrix}]

B = [\begin{matrix} 5 & 3 \\ 2 & 4 \end{matrix}]

Swap diagonal entries 5 and 4.
$[\begin{matrix} 4 & 3 \\ 2 & 5 \end{matrix}]$
Negate off-diagonal entries 3 and 2.
$[\begin{matrix} 4 & -3 \\ -2 & 5 \end{matrix}]$

The final answer is shown below.

[\begin{matrix} 4 & -3 \\ -2 & 5 \end{matrix}]