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Matrices.
How would you work this problem?
USE MATRICES TO SOLVE:
{ x + y + z = -4
{2x - y + 3z = 1
{3x + 2y - z = 4
Thanks.
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Haha. Matrices are so hard. Here's an easier way. (I've done this exact problem before.
Pick two of the equations.
For clarity's sake the top one is one the middle is 2 and the bottom is 3
{ x + y + z = -4
{2x - y + 3z = 1
{3x + 2y - z = 4
I'll pick the top two.
Then add them together (or subtract)
2x+x=3x.
The y's cancel out. The z's =4z and -4+1=-3.
3x+4z=-3.
Now, pick a different pair of equations. One is going to be one you used before. We are going to try to eliminate the y value.
I'm using equations 2 and 3, and adding them. I'm going to rewrite it and multiple by 2 for equation 2. This gives me:
2(2x-y+3z)=(1)2
Distribute.
4x-2y+6z=2.
Add this to equation 3.
7x (y's cancel) +5z=2.
Now we do the same for our solutions.
3x+4z=3
7x+5z=2
I hope you get it from here.
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ah the memories. it involes using matrix opperations, flip back a few pages and you should see what you are allowed to do, like adding rows, multiplying by a constant and such.
the answer you should get is
x=3
y=-4
z=-3
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