The matrix is .

Find .

Determinent of is .

If is asquare 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 .

.

If and are inverse matrices then .

Find .