Answer
$(-1, 5, 2)$
Work Step by Step
A: $x-y+z=-4$
B: $3x+2y-z=5$
C: $-2x+3y-z=15$
2A+C
$2*(x-y+z)+(-2x+3y-z)=2*(-4)+15$
$2x-2y+2z-2x+3y-z=-8+15$
$2x-2x-2y+3y+2z-z=7$
$y+z=7$
3B=C
$3*(3x+2y-z=5)$
$9x+6y-3z=15$
$-2x+3y-z=15$
$9x+6y-3z=-2x+3y-z$
$11x+3y-2z=0$
-3A+B
$-3*(x-y+z)+3x+2y-z=-3(-4)+5$
$-3x+3y-3z+3x+2y-z=12+5$
$5y-4z=17$
$y+z=7$
$5y-4z=17$
$4(y+z)+(5y-4z)=4*7+17$
$4y+4z+5y-4z=28+17$
$9y=45$
$9y/9=45/9$
$y=5$
$y+z=7$
$5+z=7$
$z=2$
$x-y+z=-4$
$x-5+2=-4$
$x-3=-4$
$x=-1$
