00:01
Okie -dokey, we want to find a determinant of this 3x3 -matrix, and i hope you can see that method of minor matrices is going to be the easiest way to do this, because we have a 0 value here means we only have to work out 2 minor matrix 6 rather than 3.
00:15
Okay, so taking from our top row, we've got minus 3 lots of deleting this column in this row, 5 minus 2, 4, 2.
00:28
And taking the last lot, we've got six lots of the minor matrix deleting this row of this column, 6514, 6 .14.
00:39
And i'll hope you know that the determinant of a 2x2 matrix, given the form a, b, c, d is equal to ad minus b, c.
00:50
Okay, so working out the first matrix, we've got minus three lots of 10, minus, minus two times, 4 which is going to be plus minus 2 times 4 which is just 8.
01:05
Okay and then over here we've got plus 6 lots of 6 times 4 which is going to be 24 minus remember it's here 5 times 1 minus 5.
01:22
Okay so 10 plus 8 is 18...