00:01
We want to solve the system using either gaussian elimination with back substitution or gauss jordan.
00:06
And so let me get this into an augmented matrix.
00:09
I'll do gauss jordan.
00:12
We've got the elements 4, 12, negative 7, negative 20, augmented with 26, and 3 -9 -5, negative 28 with 32.
00:25
So we can first take, let's take row 1 and divided by 4.
00:39
So we get 1, 3, negative 7, 4ths, negative 5, and 26 4ths, or 13 halves.
00:59
And i'll leave this alone.
01:07
Now let's get a 0 in row 2 by taking row 2.
01:10
And subtracting three times row one.
01:16
It'll look up to new row two of 3 minus 3, 9 minus 9.
01:23
Negative 5 minus 3 times negative 7 4th.
01:31
That'd be like negative 5 plus 21 4ths.
01:37
Or in 4th, it'd be negative 24th.
01:41
So that'd be 1 4th.
01:47
And then we would have negative 28 minus 3 times negative 5 or negative 28 plus 15.
01:56
Negative 28 plus 15 is negative 13.
02:10
And we'll have 32 minus 3 times 13 halves or 32 minus 3 times 13 is 39.
02:22
And 32 in halves is, or 32 in halves would be 64 halves is 32 and 64 minus 39 is 25 halves...