Chapter 9 - Section 9.1 - Solving Systems of Linear Equations in Three Variables and Problem Solving - Exercise Set - Page 638: 25

$(x,y,z)= (0,1/2,-4)$

Subtracting the 1st equation from the 2nd equation gives us $$-4x-4y-2z=6$$ We add this to the third equation to get... $$3z=-12$$ or $z=-4$ Plugging that back into the equations gives us $x+2y=1$ and $$-3x-2y=-1$$ When we add we get $$-2x=0$$ $$x=0$$ Plugging that back in, $$-3x-2y=-1$$ $$-2y=-1$$ $$y=1/2$$