Question 276629
1 1 2 | 5
2 1 1 | 5
4 0 1 | 5 
3 x 3 Matrix - Can not get rid of the 4...
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Subtract 2 times 1st row from 2nd
Subtract 4 times 1st row from 3rd

1  1  2 | 5
0 -1 -3 | -5
0 -4 -7 | -15
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Get rid of the negatives:
1  1  2 | 5
0  1  3 | 5
0  4  7 |15
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Subtract 4 times the 2nd from the 3rd
1  1  2 | 5
0  1  3 | 5
0  0 -5 |-5
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Solve the 3rd equation:
z = 1
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Substitute into the 2nd equation and solve for "y":
y = 2
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Substitute into the 1st equation and solve for "x":
x = 1
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Cheers,
Stan H.