00:03
Let's find the determinant of this square matrix using expansion by cofactors.
00:08
Expansion by cofactors tells us that the determinant would be a11, c11 plus a12, c12, plus a13, c13.
00:25
A11 is element in row 1, column 1, which is 3.
00:31
C11 is simply minor 11.
00:34
Which is found by deleting row 1 and column 1.
00:39
So we have 2 -3 -1 -0.
00:44
A -1 -2 is element in row 1, column 2, or 1.
00:50
C -1 -c -1 -2 is a negative of the minor 1 -2, which is found by deleting row 1 and column 2.
00:57
So we have negative 3 -1 -10.
01:02
A -1 -3 is element in row 1, column...