5x + 4y + 3z = 2 5 4 3 2
2x + 3y + 4z = 5 2 3 4 5
2,求a值
2x - y + 3z = 4 2 -1 3 4
x + y + az = 3 1 1 a 3
x + ay + z = 3 1 a z 3