后面的x应是z
9x+4y+z=10①、9x+2y+3z=1②、3x-4y+2z=5③
①-②得
2y-2z=9④
①-3*③得
16y-5z=-5⑤
8*④-⑤得
-11z=77
z=-7
z=-7代入④得2y+14=-5
y=-5/2
y=-5/2、z=-7代入①得
9x-10-7=20
x=3
x=3、y=-5/2、z=-7