Find the complete solution of the linear system, or show that it is inconsistent. (If the system has infinitely many solutions, express your answer in terms of t, where
x = x(t),

y = t,
and
z = z(t).
If there is no solution, enter NO SOLUTION.)


2x + 4y − z = 15
x + 2y + 4z = 12
x + 2y − 2z = 6