You can put this solution on YOUR website! 3x-y-2z= 18
2x+y-2z=15
x+3y-z=10
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Pick one of the variables and eliminate it.
eg, to eliminate y, add eqn 1 & eqn 2.
Then multiply either eqn 1 by 3 and add to eqn 3.
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Now you have 2 eqns in x & z.
etc
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Or you can use a matrix to solve it.
email via the TY note for help or to check your work.
Pick a pair of equations and a letter to eliminate.
[Note: There are 6 different ways to start, all correct!]
I will pick the first two equations and y to eliminate,
because it happens to be the easiest because all you have to
do is add them and y will be eliminated:
Now pick a different pair of equations and eliminate the
SAME letter eliminated first.
[Note: we have to pick one of the same equations again, but
we must pick the third equation this time.]
So I will pick the first and third equations and y to eliminate:
To eliminate y we multiply the first equation through by 3
Now we have 2 equations in 2 letters to solve:
We can eliminate x by multiplying the first equation through by -2
Substitute that in
Substitute z=-2 and x=5 in any one of the original equations:
Answer: (x,y,z) = (5,1,-2)
Edwin
