91Ó°ÊÓ

The given matrix is

$\left|\begin{array}{ccc}2& -3& -4\\ -1& 2& -3\\ 0& -1& -2\end{array}\right|$

We have to find the minor of$a_2.$

To evaluate the minor of$a_2$

Let's eliminate the row and column that contains$a_2$

Then write the remaining determinants as $2×2$matrix.

So, the matrix is

$$\begin{gathered} \left|\begin{array}{cc}-3& -4\\ -1& -2\end{array}\right| \\ =(-3)(-2)-(-4)(-1) \\ =6-4 \\ =2 \end{gathered}$$

Thus, the minor of$a_2$is$2.$

The given matrix is

$\left|\begin{array}{ccc}2& -3& -4\\ -1& 2& -3\\ 0& -1& -2\end{array}\right|$

We have to find the minor ofrole="math" localid="1644566412877" $b_2.$

To evaluate the minor of$b_2$

Let's eliminate the row and column that contains$b_2$

Then write the remaining determinants as $2×2$matrix.

So, the matrix is

$$\begin{gathered} \left|\begin{array}{cc}2& -4\\ 0& -2\end{array}\right| \\ =\left(2\right)(-2)-\left(0\right)\left(\_4\right) \\ =-4-0 \\ =-4 \end{gathered}$$

Thus, the minor of$b_2$is$-4.$

The given matrix is

$\left|\begin{array}{ccc}2& -3& -4\\ -1& 2& -3\\ 0& -1& -2\end{array}\right|$

We have to find the minor of$c_2.$

To evaluate the minor of$c_2$

Let's eliminate the row and column that contains $c_2$

Then write the remaining determinants as $2×2$matrix.

So, the matrix is

$$\begin{gathered} \left|\begin{array}{cc}2& -3\\ 0& -1\end{array}\right| \\ =\left(2\right)(-1)-\left(0\right)(-3) \\ =-2-0 \\ =-2 \end{gathered}$$

Thus, the minor of$c_2$is$-2.$