Question 246181
x-y-z=6
x-2y-3z=14
x-3y-7z=28 
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Subtract the 1st Eq. from the 2nd
Subtract the 1st Eq. from the 3rd.
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x-y-z=6
0-y-2z=8
0-2y-6z=22
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Subtract 2 times the 2nd Eq from the 3rd.
x-y-z=6
0-y-2z=8
0-0-2z=6
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Solve the 3rd equation for "z":
-2z = 6
z = -3
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Substitute z = -3 into the 2nd Eq. and solve for "y":
-y-2(-3) = 8
-y + 6 = 8
y = -2
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Substitute z=-3 and y=-2 into the 1st Eq and solve for "x":
x-(-2)-(-3) = 6
x+2+3 = 6
x = 1
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Cheers,
Stan H.