a·x + (3·a + 1)·y - (2 - a)·z = -a
2·x + 5·y + 4·z = -2
2 * I - a * II
y·(a + 2) - 2·z·(a + 2) = 0 --> y = 2·z ∨ a = -2
2·x + 5·(2·z) + 4·z = -2 --> x = - 7·z - 1
Lösung
[- 7·z - 1, 2·z, z] --> [- 1, 0, 0] + r * [- 7, 2, 1]
Probier das mal aus und rechne es nach.