00:01
In this question, we are asked to determine the rank and nullity of the given matrix.
00:05
And to do that, we need to reduce it to a row echelon form.
00:09
To reduce it to a row echelon form, we need to multiply the first row by negative 3 and add it to the second row, multiply the first row by 3 and add it to the third row, and multiply the first row by negative 4 and add it to the last row.
00:38
We are doing that to get rid of the entries below 1, to get rid of these entries.
00:46
We will rewrite the first row.
00:54
In the second row, we are going to get 0.
00:58
4 times negative 3 is negative 12.
01:01
Negative 12 minus 4 is negative 16.
01:07
And it's going to be pretty much the same for all other entries, right? because they're the same.
01:12
So it's going to be negative 16 three times.
01:16
And then it's going to be 8 times negative 3 is negative 24.
01:20
And negative 24 minus 24 is negative 48.
01:24
Now let's move on to the third row.
01:29
We are going to get 0.
01:30
Then 4 times 3 is 12.
01:34
12 plus 0 is 0.
01:39
Sorry, 12 plus 0 is 12.
01:41
And it will repeat itself like for the other entries, right? because they're the same basically.
01:49
12, 12.
01:50
And 8 multiplied by 3 is 24.
01:53
And 24 plus 12 equals to 36.
01:56
Finally, in the last row, we are going to get 0.
02:01
Then 4 times negative 4 is negative 16...