y+2z=4y=4-2z代入(1)x+8-4z=3 (4)z+2x=5 (3)(4)+(3)×4x+8-4z+4z+8x=3+209x=15所以x=5/3z=5-2x=5/3y=4-2z=2/3
该方程组无解
