we are given to find
[tex] a_2_3 [/tex]
we know that
[tex] a_i_j [/tex]
where
i is number of rows
j is number of column
Here , we get
i=2
and j=3
so,
[tex] a_2_3 [/tex] means second row and third column
we can look at matrix and find element
we can see that
that element is -21
so,
[tex] a_2_3 =-21[/tex]...........Answer