Purplemath: Minors and Cofactors: Expanding Along a Row

A "minor" is the determinant of the square matrix formed by deleting one row and one column from some larger square matrix. To find the determinant of the matrix A, you have to pick a row or a column of the matrix, find all the cofactors for that row or column, multiply each cofactor by its matrix entry, and then add all the values you've gotten. The resulting sum is the value of the determinant of the matrix A. The resource explains the process for using minors and cofactors to compute a determinant of a matrix with help of an solved example.