2x+3y+4z=56①3x+4y+5z=74②4x+5y+6z=92③②-① x+y+z=18④2x+2y+2z=36①-2x④y+2z=20⑤2x④-⑤2x+y=16⑥y=16-2x⑤-⑥z-x=2⑦z=x+22x①-③y+2z=20本题解不唯一，多解例如x=8.y=0.z=10x=6,y=4,z=8x=4,y=8,z=6
