00:01
Augment the matrix 2 -1 -1 -324, negative -24 with a 3 -3 -3 identity.
00:12
And get it in a reduced row -ash -line form, that's a way to find the inverse without a calculator.
00:17
So let's take half row 1, and that would be 1 -1 -1 -5 -1 -5 -0.
00:35
Next, let's take, let's replace row 2 with row 2 minus row 1 and let's replace row 3 with row 3 minus 4 times row 1.
00:56
We can do them simultaneously.
01:06
Then we would get 0 4 3 halves negative 1 half 1 0 2 0 2 negative 20 1.
01:28
Then let's do a couple more things.
01:36
Let's take 1 4 1 4 1 012 of row 2 and let's take that would be 0138 negative 1 8th 1 4th 0.
02:06
We can then replace row 1 by adding rows 1 and 2 together that'll get a 0 in column 2 and let's replace row 3 with row 3 minus 2 times row 2.
02:22
So then we'll get a new row 1 of 1 078.
02:26
3 eighths, 1 4th, 0...