00:01
So for this problem, we are given a matrix a, and we want to calculate our major, or our minor, i mean, m11, and then we're going to calculate our co -factor.
00:15
So essentially, since we want to find our minor 1 -1, we're going to cross out our first row from our first one, and our first column, that comes from our second one, and then we're just going to find the determinant of our remaining square.
00:32
1 -1 to calculate this determinant, we know we're going to multiply across the first diagonal.
00:37
So we get 20, and then we're going to subtract the product across our second diagonal.
00:42
So this will give us 20 minus 0, which is just 20...