Question 258522
4x+2y+z=7
2x+2y-4z=-4
x+3y-2z=-8 
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Rearrange the equations
x+3y-2z=-8 
2x+2y-4z=-4
4x+2y+z=7
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Divide thru the 2nd equation by 2:
x+3y-2z=-8 
x+y-2z=-2
4x+2y+z=7
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Subtract the 1st from the 2nd
Subtract 4 times the 2nd from the 3rd
x+3y-2z=-8 
0x-2y+0z=6
0x-2y+9z=15
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Solve the 2nd equation for "y":
y = -3
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Solve the 3rd 3equation for "z":
-2*-3 + 9z = 15
9z = 9
z=1
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Substitute for y and for z to solve for "x":
x + 3*-3 -2*1 = -8
x - 11 = -8
x = 3
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x = 3 ; y = -3 ; z = 1
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Cheers,
Stan H.
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