Chapter 9 - Section 9.1 - Solving Systems of Linear Equations in Three Variables and Problem Solving - Exercise Set - Page 638: 24

$(2, -1, 0)$

A: $7x+4y=10$ B: $x-4y+2z=6$ C: $y-2z=-1$ B+C $x-4y+2z+y-2z=6-1$ $x-3y=5$ $x-3y=5$ $7x+4y=10$ $4*(x-3y)+3(7x+4y)=4*5+3*10$ $4x-12y+21x+12y=20+30$ $25x = 50$ $25x/25 = 50/25$ $x=2$ $7x+4y=10$ $7*2+4y=10$ $14+4y=10$ $4y=-4$ $4y/4=-4/4$ $y=-1$ $y-2z=-1$ $-1-2z=-1$ $-2z=0$ $-2z/-2=0/-2$ $z=0$