+129899 7 Det = [ 5 * 3] - [5 * 2] = 15 - 10 = 5
8 Det......copy the first two columns again
3 5 2 3 5
5 3 1 5 3
2 4 2 2 4
Multiply down the diagonals and sum the products
[ (3 * 3 * 2) + (5 * 1 * 2) + (2 * 5 * 4)] = [ 18 + 10 + 40 ] = 68
Multiply up the diagonals and sum the products
[ (2 * 3 * 2) + (4 * 1 * 3) + ( 2 * 5 * 5) ] = [ 12 + 12 + 50] = 74
Subtract the second result from the first
Det = 68 - 74 = - 6
+129899 7 Det = [ 5 * 3] - [5 * 2] = 15 - 10 = 5
8 Det......copy the first two columns again
3 5 2 3 5
5 3 1 5 3
2 4 2 2 4
Multiply down the diagonals and sum the products
[ (3 * 3 * 2) + (5 * 1 * 2) + (2 * 5 * 4)] = [ 18 + 10 + 40 ] = 68
Multiply up the diagonals and sum the products
[ (2 * 3 * 2) + (4 * 1 * 3) + ( 2 * 5 * 5) ] = [ 12 + 12 + 50] = 74
Subtract the second result from the first
Det = 68 - 74 = - 6
