0:00
Hello.
00:01
So here we start with a matrix a and then we put a vertical line and then we put the three by three identity.
00:08
So if we have a concatenating with the three by three identity, we get what we see here.
00:13
Now we want to go ahead and we want to get the identity on the left hand, the left side of the vertical bar by using elementary row operations to put us into row echelon form.
00:26
So we want a one, well, we have a one already in the leading spot here.
00:31
So we want to have zeros beneath it.
00:33
So let's do, for row two, let's do row two equals to one half of row two, right? so therefore, row two is equal to row two over two.
00:48
And row three equal to, well, row three plus one half of row two.
00:58
Okay, and then that gets us, well, one, zero, two, and then zero, one, five, halves, and then zero, zero, one half, and then we have our vertical bar, and then we have one, zero, one half, one half, zero, and then negative one half, one half, one half, okay? okay.
01:26
And now, let's, again, we have ones here, one zero.
01:32
We need a one in our last pivot spot in the third row, third column, with zeros above it...