Question 841119
Solve the following linear system using the Echelon Method.
x+2y− z= −1 
2x − 3y + 2z = 15 
−3x+ y+4z=−19
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Subtract 2 times 1st from 2nd
Add 3 times 1st to 3rd
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x  +2y − z  = −1 
0x -7y + 4z = 17
0x +7y +  z = -22
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Add the 2nd to the 3rd::
x  +2y − z  = −1 
0x -7y + 4z = 17
0x +0y + 5z = -5
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Solve the 3rd for "z"::
z = -1
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Substitute for "z" in the 2nd and solve for "y":
0x - 7y -4 = 17
-7y = 21
y = -3
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Substitute for "z" and for "y" in the 1st and solve for "x"::
x -6 + 1 = -1
x = 4
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Cheers,
Stan H.