00:01
Okay, so we need to find the solution to the system of equations.
00:06
So what i'm going to do is take my first equation, and i'm going to multiply it by negative 1.
00:15
So that's going to give me negative 2x plus 3y minus z equals negative 5.
00:27
Then i'm going to take my second equation and multiply that by 2.
00:30
So our xs will cancel out.
00:33
So that's going to give me 2x plus 6 plus 16 z equals 44.
00:50
All right.
00:51
So it's going to give us those cancel out.
00:57
9y plus 15 z equals 39.
01:09
Now we're going to take our second and third equation and combine them.
01:13
So i'm going to do the same thing i did with the first equation to the third equation.
01:20
So i'm going to multiply it by negative 1.
01:23
And that's going to give us, i'm first going to write my second equation and multiply it.
01:33
So for our x is to cancel all, it needs to be 3x.
01:37
So you multiply that whole thing by 3.
01:39
So 3x plus 9 plus 24z equals 66.
01:49
Then my third equation, again, multiplied by negative 1, so minus 3x plus y, so we're going to change the sons, minus 2z equals negative 12.
02:03
All right, so we're going to combine these.
02:05
Those cancel out.
02:06
This is going to give us 10y plus 22 z equals 54.
02:23
Okay, now we are going to get rid of our ys with these two equations right here.
02:32
So the least common multiple at 10 and 9 is 90.
02:37
All right, well, we're going to multiply this one by 9, and this one by negative 10...