00:01
We want to use kramer's rule to see if this matrix has a coefficient matrix has a solution or not.
00:08
And to do that, we need to get the determinant.
00:10
So i wrote down the coefficient matrix here, and i took the determinant, and that determinant was 168.
00:17
Therefore, that tells me it does have a solution.
00:20
So now we're going to use kramer's rule to find the actual solutions.
00:25
To do that, i'm going to take the answer matrix, and i'm going to put that in place.
00:30
Place of x, leave everything else in there, and that's going to give me the determinant about x.
00:36
So i'm going to pause and get that on my calculator.
00:39
When i did, i got that on my calculator, did the determinant, and got a value of 84.
00:44
Now i'm going to do the same thing with my y column.
00:47
I'm going to put the answers here in the y column and find its determinant.
00:53
Now when i did that, i put the two, six, and twelve back in place of my x column, and only replaced three, six, and nine with those values.
01:02
So that's going to be called the determinant about y and that gave me a value of negative 56.
01:07
And lastly, we're going to maintain the x and y column just as they are, but now i'm going to take the answer matrix and put it in place of the z column.
01:17
So i'm going to pause and get that value.
01:20
Upon placing those values, i got the determinant about z, which i got 1344.
01:27
Now, so what are our answers? our answer for x is going to be the determinant...