00:01
In this problem, we are asked to solve the system using matrices.
00:06
One thing to notice, though, is in the third equation, we have an x and a y, but no z.
00:15
So i'm going to reorder the terms and the equations.
00:19
So the system i'm actually going to solve will be the same thing.
00:25
I'm just going to reorder it.
00:26
So i have a zero in the first column in the third one.
00:33
Row.
00:33
So i have 3z plus 4x minus y equals 6 and then negative 5 z minus 8 x plus 3y equals negative 6 and then i'd have 5x minus 4y equals negative 9.
00:57
So i'm doing this to line up the variables and make the augmented matrix a little bit easier.
01:09
So to write down my augmented matrix, i'd have 3, 4, negative 1, 6, negative 5, negative 8, 3, negative 6, 0, 5, negative 4, negative 9.
01:26
So then when i do this, i want to change this first value to a 1.
01:36
So i'm going to take 2 times row 1 and add it to row 2, and that will become my new row 1.
01:45
So i have 1, 0, 1, 6.
01:50
The other two rows are going to stay the same.
01:52
Negative 5, negative 8, 3, negative 6, 0, 5, negative 4, negative 9...