2x + 9y + 3z = -8
So, 2x = -8 - 9y - 3z
x = -4 - (9/2)y - (3/2)z
Let y = s and z = t
Then, x = -4 - (9/2)s - (3/2)t
y = 0 + (1)s + (0)t = s
z = 0 + (0)s + (1)t = t
(s and t are parameters (random real numbers))