Answer
$x=-3$
$y=-1$
$z=-1$
Work Step by Step
Using elimination for the first two equations:
$2x - y + 2z = -7$
$-x + 2y - 4z =5$
Multiply both sides of the first equation by $2$:
$4x - 2y + 4z = -14$
$-x + 2y - 4z =5$
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$3x=-9$
$x=-3$
Then continue to use elimination for the first and third equations:
$2x - y + 2z = -7$
$x+4y-6z=-1$
Multiply both sides of the first equation by $3$:
$6x - 3y + 6z = -21$
$x+4y-6z=-1$
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$7x+y=-22$
Substitute $x=-3$:
$7(-3)+y=-22$
$y=-1$
Solve for z: $-(-3) + 2(-1) - 4z =5$
$-4z=4$
$z=-1$
