Answer
(a) The minors are given by:
\begin{align*}
M_{11}&=-17, \quad M_{12}=-52, \quad M_{13}=-54,\\
M_{21}&=-18, \quad M_{22}=16, \quad M_{23}=5,\\
M_{31}&=-2, \quad M_{32}=-15, \quad M_{33}=-33.
\end{align*}
(b) The cofactors, are given by:
\begin{align*}
C_{11}&=-17, \quad C_{12}=52, \quad C_{13}=-54,\\
C_{21}&=18, \quad C_{22}=16, \quad C_{23}=-5,\\
C_{31}&=-2, \quad C_{32}=15, \quad C_{33}=-33.
\end{align*}
Work Step by Step
Given
$$
\left|\begin{array}{rrr}{-3} & {4} & {2} \\ {6} & {3} & {1} \\ {4} & {-7} & {-8}\end{array}\right|.
$$
(a) The minors are given by:
\begin{align*}
M_{11}&=-17, \quad M_{12}=-52, \quad M_{13}=-54,\\
M_{21}&=-18, \quad M_{22}=16, \quad M_{23}=5,\\
M_{31}&=-2, \quad M_{32}=-15, \quad M_{33}=-33.
\end{align*}
(b) The cofactors, are given by:
\begin{align*}
C_{11}&=-17, \quad C_{12}=52, \quad C_{13}=-54,\\
C_{21}&=18, \quad C_{22}=16, \quad C_{23}=-5,\\
C_{31}&=-2, \quad C_{32}=15, \quad C_{33}=-33.
\end{align*}
