-3x+y+z=-1, 2x+y-z=-4, x-y+z=7 getting sums -x+2y=-5, 3x=3, from the second we can easily see: x=1, which makes -x+2y=-5 become: -1+2y=-5, 2y=-4, y=-2, making x-y+z=7 become: 1--2+z=7 1+2+z=7, z=4 So the solution to the system of equations is: (1,-2,4)
