00:03
All right, this question asks us to find the determinant of a by expanding about the first column.
00:10
They want us to go about the first column because we have two zeros here.
00:15
So our determinant of a is going to equal zero times its co -factor, which is negative 1, first row, first column.
00:26
So 1 plus 1 is 2.
00:28
Determinant of the four things that are not in the same row or same column, 3, 5, 4, 1.
00:34
Which means that that's going to give us a zero there.
00:39
Then we had negative 1.
00:40
It's in the second row first column, so it's negative 1 cubed.
00:45
The four things that are not in the same row, same column are 2, 8, and 4, and 1...