Question 1120808
2x +y - z=4
3x +5y +z=16
 x -2y -5z=3
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Add the 1st 2 equations --> 1 eqn in x & y
Multiply the 1st equation by 5, then subtract eqn 3 --> another equation in x&y.
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Solve for x or y, the sub and find the other 2 variables.
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x+2y+z=4
x+3y-2z=2
3x +y+2z =6
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Eliminate any of the 3 variables first, etc.
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