# How to find all the minors and cofactors of the matrix #A=((1, -2, 3), ( 6, 7, -1 ), (-3, 1, 4))#?

##### 1 Answer

The *minors* of a matrix are the determinants of the smaller matrices you get when you delete one row and one column of the original matrix. The *cofactors* of a matrix are the matrices you get when you multiply the minor by the right sign (positive or negative).

#### Explanation:

There is a minor and a cofactor for every entry in the matrix -- so that's 9 altogether! I'll just go through a few of them.

The minor for the first row and column is called

Then we take the determinant of this matrix, which is

To find the corresponding cofactor, called

Let's do one more. To find the minor

Then we take the determinant of this matrix, which is

To find the cofactor