Step-by-step explanation:

third order determinant = determinant of 3×3 matrix A

given ∣A∣=11

det (cofactor matrix of A) =set (transpare of cofactor amtrix of A) (transpare does not change the det)

=det(adjacent of A)

{det (cofactor matrix of A)}

2

={det (adjacent of A)}

2

(Using for an n×n det (cofactor matrix of A)=det (A)

n−1

)

we get

det (cofactor matrix of A)

2

={det(A)

3−1

}

2

=(11)

2×2

=11

4

=146.41

꧁Answer꧂