find the minor M13 and its cofactor C13 of the matrix

Question

1.find the minor M13 and its cofactor C13 of the matrix

6	-4	16
-6	4	-12
2	-6	12

2.calculate the determinant

9	4	-9
0	-6	2
45	8	5

 

Answer 1

1.

The matrix is .

Find .

If is a square matrix  then minor of its entry is denoted by .

It is defined as the determinent of the submatrix obtained by removing from its row and column.

is the minor of element in .

Therefore, .

.

Find Cofactor .

Cofactor of the entry is denoted by and is defined as .

.

Answer 2

2.

The matrix is .

Find .

Determinant of is .