00:01
We want to get this solved by putting, getting, making, getting a 1 in each one of these positions and zeros in all of the other positions here.
00:09
Well, i like that first row is already taken care of, so i don't want to make any changes there.
00:14
I want to work with equations 2 and 3 real quick.
00:17
So the first thing i'm going to do is in that third row, 1 -1 -2, there's just a lot of repetition of writing here.
00:24
I'm going to go and divide everything by 2, negative 2.
00:30
So it's going to be 0, 1, negative 2, and 0.
00:35
That just makes my number smaller.
00:37
So now what i'm going to do is take this equation, multiply it by 2.
00:41
I'm going to add it to this equation here.
00:44
We're going to add it here.
00:46
And then i'm going to replace this equation 2.
00:49
So that means i'm going to go leave the first one alone, negative 1.
00:55
I'm going to leave the third one alone.
00:57
I always like to put those in first.
00:59
Now let's go do a modification.
01:01
0 times 2 is 0 plus 0 is 0.
01:05
3 times 2 is 6 plus 1 is 7.
01:09
2 times 1 is 2 plus negative 2 is 0.
01:14
7 times 2 is 14 plus 0 is 14.
01:19
So that is very nice because now i can divide that by 7 and i would have that row taken care of.
01:27
So i'm going to have that we have, let me come here below.
01:32
1 -1 -2, negative 1, 0 -1 -0 -2, and 0 -1 -2, and 0 -1 -2 and 0.
01:40
So what can we do now? i'm going to go through, and i'm going to take equation 1 and 3 and add these together.
01:50
So i'm going to add these together, and then i'm going to replace that in equation 1, because i see my 2s are going to eliminate.
01:58
So i want to come over here and write these bottom two down.
02:02
010 and 2.
02:04
01, negative 2 and 0.
02:06
Now let's add 1 plus 0 is 1.
02:10
1 plus 1 is 2.
02:12
2 and negative 2 is 0...
